1. Maths

    A radioactive substance decays exponentially in such a way that after 50 years, 60% of the initial amount remains. Find an expression for the quantity remaining after t years.

    asked by Rish on June 15, 2014
  2. Chemistry

    carbon 14 has a half life of 5715 years. If you start with a 5 gram sample of 14C, what mass is left after 15,000 years?

    asked by Mima on April 24, 2012
  3. math

    the current population of a threatened animal species is 1 million, but it is declining with a half-life of 20 years. how many animals will be left in 60 years?

    asked by JT on October 17, 2017
  4. Maths

    a man earns ¡ê20000 per annum. he receives a 6% increase each day. how much does he earn after eight years? how many years does he take for jpgis salary to double?

    asked by Anonymous on October 16, 2015
  5. economics

    use the expenditure equation for gdp=c+i+g+xn find the values for each sector for the years 1929 and 1933. determine the precentage change for the two years.

    asked by patricia on April 20, 2011
  6. physics

    A steel ball of mass 0.300 kg is fastened to a cord that is 70.0 cm long and fixed at the far end. The ball is then released when the cord is horizontal. At the bottom of its path, the ball strikes a 2.50 kg steel block initially at rest on a frictionless

    asked by Taylor on March 28, 2011
  7. Math

    At age 2, a cat or dog is considered 24 "human" years old. Each year after age 2 is equivalent to 4 "human" years. Fill in the expression [24 + X (a-2)] so that it represents the age of a cat or dog in human years. Copy the chart and use your expression to

    asked by Wendy on August 30, 2007
  8. Math

    At a pet store, Rhonda paid $11.50 for 3 dog bowls and 4 bones. Kelly paid $13 for 2 dog bowls and 8 bones. How much will Andrew pay for 4 dog bowls and 2 bones?

    asked by Jesus on October 11, 2013
  9. Algebra

    RICHARDS age in 15 years will be twice what it was 7 years ago. How old is richard

    asked by Anonymous on October 13, 2015
  10. Math

    In 8 years, a girl will be 3 years older than twice her present age. How old is she?

    asked by Ashleigh Cunningham on October 24, 2013
  11. physical science

    I have 50 grams of an isotope. How much of it will i have in 10 years if it has a half life of 10 years

    asked by Angelique on June 15, 2017
  12. math

    In five years time thabo will be three times as old as he was nine years ago.how old is he now

    asked by tauqir adams on July 22, 2016
  13. Math

    What is the answer to the below math problem? 78000 x (1.7% x 20 years) + (1% x 10 years)

    asked by Mike on July 26, 2011
  14. Science

    In how many years will a 80 mg of sample of C14 with t1/2 5760 years be reduced to 20 mg

    asked by Uzma Amin on August 11, 2018
  15. algebra

    A radioactive substance decays according to the formula A=A0e^kt where A0 is the initial amount of substance (in grams) A is the amount of substance(in grams) after t years k is a constant The half-life of the substance is 10 years.If we begin with 20g of

    asked by enhle on April 3, 2015
  16. Math

    Serena wants to borrow $15 000 and pay it back in 10 years. Interest rates are high, so the bank makes her two offers: • Option 1: Borrow the money at 10%/a compounded quarterly for the full term. • Option 2: Borrow the money at 12%/a compounded

    asked by Maame on May 20, 2012
  17. elementary brainteaser

    My college teacher gave us a brainteaser for elementary kids and I can not figure it out! next letter: s,m,h,d,w,m,_? ok seconds, minutes, hours, days, weeks, months, ?? then what? next is years years? Ok, yes. Years is the next term in the sequence I

    asked by elizabeth on August 27, 2006
  18. English

    Why is it wrong to say " a child of six years old" and is possible to say "a six-year-old child"? Example: My family consists of /is made up of/ is composed of two adults and two children, six years old and ten years old. But: .... of a six-year-old child

    asked by Henry2 on July 4, 2011
  19. physical

    three blocks,each with same mass, stacked one upon the other. the bottom block rest on a frictionlesshorizontal surface and is being pulled by a force F that is parrallel to this surface.the surface where the blocks touch each other have identical

    asked by nkosingiphile on July 26, 2012
  20. spring physics check work plz

    A block (mass 0.5 kg) is hanging from the end of a spring. The spring is observed to stretch by 20 cm in order to come to equilibrium. a) What is the spring constant? F=-kx F=mg=.5(9.8)=4.9 N and x=-.2meters -4.9/-.2meters=24.5 =k should the constant be

    asked by Anonymous on August 16, 2009
  21. Math

    Columbus was born in 1451 and died in 1506. How old was he when he died? How many years ago did he die? He was 55 years old when he died He died 508 years ago

    asked by Sue on April 1, 2014
  22. math

    you are 6 years older than your sister she is 4 years older than your brother. write expressions to show your age and your sisters age if your brother is 4 years old.

    asked by debbie on January 10, 2013
  23. algebra

    painting is purchased for $250. If the value of the painting doubles every 5 years, then its value is given by the function V(t) = 250 • 2t/5, where t is the number of years since it was purchased and V(t) is its value (in dollars) at that time. What is

    asked by soka on August 6, 2011
  24. Math

    I cant figure this out! Can someone please tell me were my mistake is?? :) - a man is 3 times as old as his son. In 11 years time he will be twice as old as his son will be. Let s represent sons age in years now I did: present man: 3s son: s In 11 years

    asked by Mia on March 10, 2013
  25. Math

    A radioactive material has a half life of 500 years. A) Given 20 grams of this material, how much will remain after 1,000 years? B) Given 100 grams of this material, how much will remain after 750 years? Thank you to whom ever can help me :)

    asked by Milly on October 29, 2016
  26. Math 61 Algebra

    A person's hair length is proportional to the number of years it has been growing. After 2 years a person's hair grows 8 inches. The longest moustache on record was grown by Sain of India. Sain grew his moustache for 17 years. How long was each side of his

    asked by jeri on March 6, 2010
  27. Math (calculus )

    A company buys an office machine for $5200 on January 1 of a given year. the machine is expected to last for eight years at the end of which time its trade in value or salvage value will be 1100$. if the company figures the decline in value to be the same

    asked by Jenna on February 3, 2016
  28. Math

    A company buys an office machine for $5200 on January 1 of a given year. the machine is expected to last for eight years at the end of which time its trade in value or salvage value will be 1100$. if the company figures the decline in value to be the same

    asked by Jenna on February 3, 2016
  29. physics

    A block of mass m1 = 2.4 kg initially moving to the right with a speed of 3.3 m/s on a frictionless, horizontal track collides with a spring attached to a second block of mass m2 = 4.1 kg initially moving to the left with a speed of 1.5 m/s as shown in

    asked by Leticia on October 14, 2013
  30. Physics

    A 50 kg crate is initially at rest on a plane inclined at an angle of 30 degrees to the horizontal. A man then pulls the crate up the incline via a rope that is parallel to the inclined plane. The tension that the man imparts to the rope is 100 N, and the

    asked by Shelby on November 1, 2010
  31. phy

    A 3.50 kg block on a smooth tabletop is attached by a string to a hanging block of mass 2.80 kg. The blocks are released from rest and allowed to move freely. 1-Is the tension in the string greater than, less than, or equal to the weight of the hanging

    asked by ivan on July 18, 2011
  32. statistics

    Use the multiple regression equation to predict a person's salary. Assume that the variable A is the number of years of college. Assume that the variable B is the number of years of experience. Suppose the person has 7 years of college and 3 years of

    asked by jassi on November 13, 2012
  33. algebra

    I have a word problem in my homework that confuses me. How long is 1 billion seconds simplified into years then months then days, etc. Years then months then days as in xx years xx months and xx days to count to 1 billion seconds. Just one answer not an

    asked by Jason on September 24, 2009
  34. Statistics

    Use the multiple regression equation to predict a person's salary. Assume that the variable A is the number of years of college. Assume that the variable B is the number of years of experience. Suppose the person has 7 years of college and 3 years of

    asked by jassi on November 10, 2012
  35. Business Math ( Future ordinary Annuities)

    Howard has deposited RM1000 at the end of each month into a retirement savings plan for the last 10 years in his working life. His deposits earned an interest rate of 2.5% per month for the first 4 years and 3% per month for the rest of the years. What is

    asked by Tracy on December 10, 2016
  36. math

    B owes $3000 due 2 years from today without interest and $2000 with interest at 4% compounded quarterly due in 6 years from today.if money worth is 5% compounded semiannually what single payment made 4 years from today will discharge his debts?

    asked by AAA on February 19, 2017
  37. Finance

    Bond value and time--Constant required returns Pecos Manufacturing has just issued a 15-year, 12% coupon interest rate, $1,000-par bond that pays interest annually. The required return is currently 14%, and the company is certain it will remain at 14%

    asked by Mary on November 8, 2011
  38. Statistics

    How much more would you expect to pay for a home that has four bedrooms than for a home that has three bedrooms? Here are some data for West Lafayette, Indiana. These are the selling prices (in dollars) that the owners of the homes are asking: Table 1:

    asked by Kayse on August 5, 2007
  39. physics

    Determine the direction of frictional forces (left, right, up down) for the objects: 1) A cup resting on top of a car. The car is moving and accelerating to the right. 2) A block being pushed to the right up an incline. 3)A block being placed at the middle

    asked by taylor on September 14, 2016
  40. physics

    A block of mass m = 3 kg is attached to a spring (k = 28 N/m) by a rope that hangs over a pulley of mass M = 7 kg and radius R = 6 cm, as shown in the figure. Treating the pulley as a solid homogeneous disk, neglecting friction at the axle of the pulley,

    asked by Angelina on March 28, 2012
  41. Physics

    An inclined plane is on a table 1.4m tall. A 6kg box is hanging vertically attached to a 2kg mass on a plane with an unknown incline plane with coefficient of sliding friction of .2 . a. determine the acceleration of the system. b. if the plane is 3.5m

    asked by Mitch on December 10, 2010
  42. SS again please help me asap

    which of the following best describes the life style of up country residents? homes were decorated with portraits and silver men and women worked hard to operate farms houses had special rooms for visitors families lived in bustling towns with close

    asked by recon sniper on November 21, 2013
  43. Physics

    if the speed of the block is 9.5 m/s at the bottom of the ramp, from what height was the block released? what is the length of the ramp?" and i know that the mass is 7 kg, initial veloctity=0, it is frictionless, and inclined at an angle of 62 degreesif

    asked by Ian on October 4, 2011
  44. Can someone help me on math?

    Calculate the simple interest for each situation. Choose THREE that have a simple interest greater than $800.00. a. $2,000.00 at 6% for 7 years *** b. $4,500.00 at 3% for 6 years *** c. $1,400.00 at 6% for 9 years d. $5,000,00 at 7% for 3 years *** e.

    asked by Soso on February 2, 2016
  45. Statistics Help Please

    How do I tell if this is a mean or a proportion 1. Insurance companies track life expectancy information to assist in determining the cost of life insurance policies. The insurance company knows that, last year, the life expectancy of its policyholders was

    asked by LT on November 12, 2007
  46. Math check my answer

    During exercise, the recommended maximum heart rate in beats per minute is modeled by the formula M = 176 – 0.8A, where M is the maximum heart rate and A is the person’s age. Approximately, at what age would you have a recommended heart rate in beats

    asked by SmartyPants on March 14, 2015
  47. Business Statistics

    Instructions: Prepare your answers using Excel and show your work to get full or partial credit. Question 1: Using the file Wages.xlsx which contains information of working individuals, for a nationwide firm (Value 7 points). a) Run Descriptive Statistics

    asked by Katie on December 14, 2011
  48. adult education

    You are a share analyst for an investment firm and are investigating the return on shares in the Mean Corporation over the last four years. The return on Mean Corporation shares over the last four years is presented. Calculate the geometric mean rate of

    asked by Stats on October 3, 2010
  49. Social Studies 8

    Which period of history was influenced by the classical Greek and Roman works? A)Renaissance B) Age of Exploration C) Technology Era D) Dark Ages

    asked by Connections Academy Student on October 1, 2015
  50. 7th grade

    If a man says he has three children who's ages are the product 36,the sum is the house number across the street and his oldest son loves chocolate cake,how old are the kids?

    asked by Reid on October 15, 2008
  51. guidance

    The way it's used in childcare today, time-out A. is the best way to discipline children of all ages.B. is often misused.C. should completely isolate the child from the rest of the class.D. should last for at least 30 minutes. The answer is B.

    asked by Amanda on October 22, 2014
  52. AP european history

    I'm writing a paper comparing and contrasting the government , art, and religion of ancient Greece, Rome, and the Middle ages and I have no idea how to even get started. Please help!

    asked by Elizabeth on August 22, 2010
  53. CDA

    The way it's used in childcare today, time-out A. should last for at least 30 minutes. B. should completely isolate the child from the rest of the class. C. is often misused. D. is the best way to discipline children of all ages. My answer is c

    asked by Kaleisha on March 21, 2015
  54. PHYSICS

    Q.1.A spring of force constant'k'is cut into two parts whoose lengths are in the ratio 1:2.The parts are now connected in paralle and a block of mass'm'is suspended at the end of the combined spring.Find the period of oscillation performed by the block.

    asked by CHIKIRSHU on December 25, 2009
  55. Math

    Translate this situation into a system of equations of the first degree in two variables and make sure you identify the variables clearly: Today, the difference in age between a father and his son is 23 years. Two years from now, the father's age will be

    asked by Danielle on January 17, 2013
  56. Math

    In 1991,the life expectancy of meals in a certain country was 69.8 years. In 1996, it was 72.7 years. Let E represent the life expectancy in year t represent years. E(t)= ____+ _____ Use the function to predict the life expecancy of maels in 2008 E(17)=

    asked by Leina'ala on May 10, 2011
  57. Financial Math

    An investment of $2500 accumulates at 6% p.a compounded semi annually for 3 years. At that time, the interest rate is changed to 5% compounded monthly. How much is the investment worth 2 years after the change in interest rate? What is interest gained at

    asked by Riya on June 13, 2014
  58. Financial mathematics

    $800,000 if your rate of return is 5.3% compounded monthly If you deposit the amount you need to achieve your goal in 20 years, how much will your savings be worth after 10 years?

    asked by Adalheidis on December 19, 2016
  59. Finance

    If upon retirement in 20 years Simon plans to invest $400,000 in a fund that earns 5%, what is the maximum annual withdrawal he can make over the following 15 years?

    asked by Melissa on July 22, 2013
  60. Math

    Abdul wants to lease an apartment for 5 years. how much money would he have paid at the end of 5 years if he pays a $400 deposit and a $525 a month in rent?

    asked by Cassie on February 8, 2009
  61. Math

    Hector rain in the city charity race for four years. His times in minutes were: 14.8, 22.3 , 26.7, and 31.9 . What was his average time for the four years to the nearest tenth of a minute?

    asked by Gianina on August 25, 2011
  62. math

    Mrs. Hart, at age 65, can expect to live for 25 years. If she can invest at 5% per annum compounded monthly, how much does she need now to guarantee herself $900 every month for the next 25 years?

    asked by Judy on April 3, 2015
  63. PFN2

    upon retirement in 20 years Simon plans to invest $400,000 in a fund that earns 5%, what is the maximum annual withdrawal he can make over the following 15 years?

    asked by shelly on October 27, 2013
  64. Math

    A sum of $850 is invested for 10 years and the interest is compounded quarterly. There is $1100 in the account at the end of 10 years. What is the nominal annual rate?

    asked by Samantha E on March 1, 2016
  65. msth

    you are planning for your kids future education. he is 8 years old now and will start in ten years. How much will you have to set aside each year in order to have 65,000.00 if the interest rate is 7%.

    asked by mark on May 23, 2011
  66. Finance

    If upon retirement in 20 years Simon plans to invest $400,000 in a fund that earns 5%, what is the maximum annual withdrawal he can make over the following 15 years

    asked by Jennifer on October 26, 2013
  67. Finance

    a. If upon retirement in 20 years Simon plans to invest $400,000 in a fund that earns 5%, what is the maximum annual withdrawal he can make over the following 15 years?

    asked by Summer on October 23, 2013
  68. ALGERBRA

    Here are two ways of investing $30,000 for 20 years: Periodic Deposit $1,500 at the end of each year Rate 5% compounded annually Time 20 years

    asked by JOHN DUNN on May 30, 2014
  69. Physics

    Is it possible for a human being who has a life expectancy of 70 years to make a round-trip journey to a part of the universe thousands of light-years distant?

    asked by Tiffany on April 30, 2008
  70. Math

    Mrs. Hart, at age 65, can expect to live for 25 years. If she can invest at 8% per annum compounded monthly, how much does she need now to guarantee herself $300 every month for the next 25 years?

    asked by Karen on September 17, 2016
  71. Mathematics

    calculate the CPI for this year and for 5 years from now. Project the price 5 years from now of an item that you commonly buy. **Dunkin Donuts Coffee**** $2.04 Please help, I know I am missing something. Thanks

    asked by tracy on November 24, 2013
  72. finance

    I'm not sure how to approach this problem What is the fair value of a 10-year annuity of $5,000 whose payment will start five years from now and last until fourteen years from now (10 payments), if the interest rate is 8%?

    asked by help w/ business on February 1, 2011
  73. physics

    Masses 19 kg and 9 kg are connected by a light string that passes over a frictionless pulley as shown in the figure ( The figure shows the 19 kg block on the table connected by a string through a pulley which is connected to the 5 kg block hanging off the

    asked by james on November 10, 2013
  74. physics

    Masses 19 kg and 9 kg are connected by a light string that passes over a frictionless pulley as shown in the figure ( The figure shows the 19 kg block on the table connected by a string through a pulley which is connected to the 5 kg block hanging off the

    asked by james on November 10, 2013
  75. Math 7th

    Ms.Anderson took a walk down her street. She noticed on her walk that her house is 2 blocks south of the post office, the grocery store is 1 block north of her house and her house is the midpoint between the post office and the video store. Which best

    asked by Anonymous on April 18, 2011
  76. us history

    How is the Seven Years War related to the French and Indian War? The French and Indian War directly caused the Seven Years' War. The French and Indian War was part of the Seven Years' War. The Seven Years' War was more of a land war than the French and

    asked by Labbayk on January 10, 2016
  77. Social Studies

    What shortage was created by the post-World War II baby boom? a. a shortage of food products b. a shortage of hospitals c. a shortage of houses d. a shortage of schools i think its a

    asked by basketball&batman on April 24, 2015
  78. physics

    I need to sketch a graph of the gravitational potential energy (y axis) of a block as a function of its kinetic energy (x axis). The block is at the top of an inclined plane. It starts from rest and slides without friction down the length of the incline. I

    asked by Nabil on March 20, 2011
  79. Physics

    A 3.9 g mass is released from rest at C which has a height of 0.9 m above the base of a loop-the-loop and a radius of 0.4 m. The acceleration of gravity is 9.8 m/s^2. Find the normal force pressing on the track at A, where A is at the same level as the

    asked by I Need Help on April 9, 2014
  80. Physical science

    Hello! 1.How can the density of a hollow lead ball filled with water be increased? a.Increase the size of the ball and add more water.* b.Remove the water and replace it with air. c.Remove the water and melt the ball into a solid sphere. d.Remove the water

    asked by HeyVSauceMichealHere on April 26, 2018
  81. Finance

    Dr. David Dunn is adding a new piece of diagnostic equipment to the department. Two similar models are offered by two different vendors, and both models would serve the needs of the clinic. both also have an estimated useful life of five years, with no

    asked by Linda on September 8, 2012
  82. physics

    A force of 40.0N is required to pull a 10.0kg wooden block at a constant velocity across a smooth glass surface on Earth. What force would be required to pull the same wooden block across the same glass surface on the planet Jupiter.

    asked by Rena on February 22, 2009
  83. physic

    a wooden block of density 860 kg per metre cube at zero degree celsius is floating on benzene liquid of density 900 kg per metre cube at zero degree celsius the temperature at which the block just submerge in Benzene is

    asked by ruchiket on August 30, 2017
  84. Mathematics

    Kelly has twice as many CDs as Lou. Tiffany has three times as many CDs as Lou. Altogether they have 372 CDs. How many more CDs does Tiffany have than Lou?

    asked by Mickaela on September 27, 2011
  85. MATH

    Kelly has twice as many CDs as Lou. Tiffany has three times as many CDs as Lou. Altogether they have 372 CDs. How many more CDs does Tiffany have than Lou?

    asked by Mickaela on September 27, 2011
  86. now mr. damon, physics

    A 63.8 kg block of silver is at initially at 107 C. 1.0 kg of ice at its freezing point is placed onto the block to cool it. As the ice melts, the water is free to flow off (so that the water never increases in temperature). After all the ice melts, what

    asked by sara on November 25, 2014
  87. Math

    Bobo bought a 1 ft squared block of cheese. He needs to cut it into 3 in. cubes. The block is yellow outside but green on the inside. How many 3 in. cubes does it have? How many of the cubes have no yellow face, one yellow face, 2 yellow face, etc. Please

    asked by Sarah on April 13, 2014
  88. Science

    A pistol of mass 2 kg fires a bullet of mass 50g. The bullet strikes a stationary block of mass ½ kg. if the block, with the bullet in it, moves with a velocity of 4 m/s the recoil velocity of the pistol will be?

    asked by Khushboo on November 21, 2015
  89. Algebra

    Bobo bought a 1 ft squared block of cheese. He needs to cut it into 3 in. cubes. The block is yellow outside but green on the inside. How many 3 in. cubes does it have? How many of the cubes have no yellow face, one yellow face, 2 yellow face, etc. Please

    asked by Sarah on April 13, 2014
  90. physics

    Problem A5: In the figure above, the two blocks are on frictionless inclines and are in static equilibrium. The block on the left has a mass of 48 Kg, and the block on the right has a mass of n3 Kg. If the left incline has a length of n1 meters, and the

    asked by frank on January 11, 2012
  91. Physics

    I was given this problem, and are having problems. I am taking AP Physics and I want to be able to understand the concept. Thank you for your help. A block of mass m = 3.65 kg is attached to a spring (k = 27.5 N/m) by a rope that hangs over a pulley of

    asked by Rodrigo on October 31, 2014
  92. statistics

    The probability that a house is burglarized in the city is 5%. If 50 houses are randomly selected, what is the probability that none will be burglarized?

    asked by Sherry on July 15, 2012
  93. technolgy

    do golden houses in venice have a back garden and could i get a picture of the back of golden house

    asked by kiran on November 15, 2007
  94. Finance

    You deposit $1000 for 5 years at 4% annual interest. In 5 years, you add $10000 to your account, but the rate on your account changes to 8% annual interest (for existing balance and new deposit). You leave the account untouched for an additional 15 years.

    asked by Basil on March 15, 2012
  95. Science

    (just a quick science question, pls correct my answer if im wrong..) Which of the following statements is true A.) there is more water on earth now than there was millions of years ago **** B.) there is less water on earth now than there was millions of

    asked by io on April 4, 2018
  96. physics

    A small block with mass 0.308 kg is sliding down a frictionless ramp that is inclined at an angle of 53.1° above the horizontal. Assume g = 9.80 m/s2. (a) As the object slides down the incline, what is the magnitude of the normal force that the surface of

    asked by Mike on February 2, 2015
  97. Probability

    A large governmental survey of dental care among children 2 to 17 years old found the following distribution of times since last visit to the dentist: (1st column)Time since last visit (1st column)6 months or less (1st column)>6 months but no more than 1

    asked by Mi on April 28, 2016
  98. algebra

    In 1990, the life expectancy of males in a certain country was 66.3 years. In 1997, it was 70.0 years. Let E represent the life expectancy in years t and let t represent the number of years since 1990. E(t)= ___t +____ round to the nearest tenth. Use the

    asked by sonia on October 23, 2009
  99. government

    the purpose of deciding important bills by a committee of the whole is to a. ensure that every member of the house has a chance to speak about the bill b. talk the bill to death c. speed up the floor debate d. make sure that both houses pass the same

    asked by jere on January 11, 2008
  100. Science

    After an avalanche, a huge block of a stone slid down a mountain and landed in the middle of a road. People in the nearby town had a very difficult time moving it out of the road, The block of stone is difficult to move because. it has a high amount of

    asked by Kennabug on March 11, 2015