Sunday
February 14, 2016

# Posts by jane

Total # Posts: 1,518

Math
Order from least to greatest. -4, -3.9, - 2/9, 2/11
October 22, 2013

chem
Nuclide X has decay constant 1.08 h-1. It can decay in 2 branches, to nuclide Y or to nuclide Z: X --> Y, with decay constant 0.43 h-1, and X --> Z, with unknown decay constant. If there are 10 moles of nuclide X at time t = 0, how many moles of each daughter will there ...
October 21, 2013

chem
No. I worked out the problem and got around 45kg but Im not sure if its right.
October 16, 2013

chem
Pu-238 is radioactive by alpha-decay (half-life 87.7 y). Each decay releases 5.6 MeV of energy. Pu-238 is sometimes used to power space probes. If all the decay energy can be converted to electric power, what mass of Pu-238 would be required to power a 22 kW space probe for at...
October 16, 2013

Chemistry
for a) i meant lower not higher
October 15, 2013

Chemistry
If we ignore the small fraction of U-234, natural uranium has a concentration of 99.28 atom% of U-238 and 0.72% U-235. Their half-lives are, respectively, 4.68*109 and 7.038*108 years. (a) In the future, will the U-238 percentage be higher or lower? (b) In Oklo, Gabon, Africa...
October 15, 2013

Chemistry
Pu-238 is radioactive by alpha-decay (half-life 87.7 y). Each decay releases 5.6 MeV of energy. Pu-238 is sometimes used to power space probes. If all the decay energy can be converted to electric power, what mass of Pu-238 would be required to power a 22 kW space probe for at...
October 15, 2013

Chemistry
write out the balanced equation when Iron(II) sulfate, potassium permanganate, and sulfuric acid react to form Iron (III) sulfate, manganese (II) sulfate, Potassium sulfate, and water.
October 14, 2013

Chemistry
Using atomic masses, If a certain batch of D2O has a purity of 99.75 weight %, what is its purity in atom (actually molecule) %
October 3, 2013

Algebra Emergency!!
Thank you guys the help is great
October 2, 2013

Algebra Emergency!!
Find the inverse of f(x)=2x+1/x-1 and please VERIFY(CHECK) Thanks so much
October 2, 2013

Algebra Emergency
and the verification?
October 2, 2013

Algebra Emergency
Find the inverse of 2/2x-1 and verify.
October 2, 2013

Chemistry
The isotopic abundance of naturally occurring hydrogen is as follows: 1H 99.985 atom % 2H 0.015 atom% When H2 gas is formed from naturally occurring hydrogen, what percentages of the molecules have molecular weights of approximately 2, 3 and 4?
October 1, 2013

Algebra
Two persons, A and B, together have \$6 less than a third person, C. If B gives \$5 to A, then A will have half as much money as c does. If A gives \$5 to B, then A will have one third of what c has. How many dollars has each?
September 29, 2013

calculus
integrating e^1/3dx i got 3e1/3 +c pls am i right
September 6, 2013

How does KH2PO4 induce controlled flocculation?
September 4, 2013

How does KH2PO4 induce controlled flocullation?
September 3, 2013

home economics
Explian craft
August 12, 2013

Science
Can anyone balance Sn 2+ to Sn4+ in basic solution as half reaction
July 20, 2013

Elementary mechanics
Given that the mass and radius of jupiter are respectively 190000000kg 7150000km.Calculate the escape velocity from the surface of the planet(a)11.2 km/s(b)33.3km/s(c)59.5km/s(d)110.4km/s
July 15, 2013

Elementary mechanics
what is common to the variation in the range and the hieght of a projectile. I'm thinking of horizontal acceleration pls what do u think
July 15, 2013

Elementary mechanics
A force of 2i+7jN acts on a body of mass 5kg for 10 seconds. The body was initally moving with constant velocity of i-2jm/s.Find the final velocity of the body in m/s, in vector form. (a)5i+12j(b)12i-5j(c)10i-7j(d)7i+10j
July 14, 2013

maths
(Q1)a+3b+2c=3,2a-b-3c=-8,5a+2b+c=9.solve for a,b&c by matrix method. (a)2,9,3(b)4,(-3),1(c)7,5,5(d)3,(-4),7 (Q2)a+2b+3c=5,3a-b+2c=8,4a-6b-4c=2.find a,b&c by Guassian method.(a)1,4,9(b)4,(-5),5(c)5,(-3),9(d)(-1),5,10
July 5, 2013

ENHANCING CHILDREN'S SELF ESTEEM
I am doing a teacher aide course online and I need you to correct my answers for me
June 19, 2013

Chemistry
636 grams of Na2CO3(s) are disolved in 3.0 liters of aqueous solution
June 14, 2013

Chemistry
For the cell diagram Pt(s)|H2(g)|H+(aq)||Cu2+(aq)|Cu(s) Write a balanced equation for the half-reaction at the cathode. The cathode is the site of reduction so copper gets reduced. So wouldn't the answer be: Cu2+(aq) -> Cu(s) + 2e-?
June 11, 2013

science
ferrous sulphate + sodium hydroxide forms ppt. ferrous hydroxide + sodium sulphate is left in the solution write a balanced chemical eqn.. for this..
June 11, 2013

statistics
a study found 37% of a new technique resulted in pregnancy and in that technique 25% resulted in multiple births what is the probabilty that the new technique produced a pregnacy and multiple births what is probability that a random selected pregnancy did not produce multiple ...
June 6, 2013

calculus 2
Test the series for convergence/divergence. The Summation from n=1 to infinity of: 1*3*5...(2n-1)/(2*5*8...(3n-1) I'm not sure what to do with the extra terms on the left.
June 5, 2013

Math
Subtract 750 grams from 3 kilograms
May 29, 2013

teacher aide
according to carl jung what are the two main ways people process information
May 26, 2013

Science (2nd Try)
To determine the boing point of a liquid, a student heats 10 mL of the liquid in a test tube and records the temperature every minute for 20 minutes. In this example, time is the what? The choices are: Independent variable dependent variable hypothesis control Is it dependent ...
May 23, 2013

Science
To determine the boing point of a liquid, a student heats 10 mL of the liquid in a test tube and records the temperature every minute for 20 minutes. In this example, time is the what? The choices are: Independent variable dependent variable hypothesis control Is it dependent ...
May 22, 2013

Math
The scooter does 40km to a litre of petrol. If I use 7.25l how far did the scooter travel
May 21, 2013

Physics
A circular plate of radius 0.5 m is placed perpendicular to the direction of the magnetic field of 0.5 Tesla. What is the change of flux in the plate if it rotates and its plane becomes parallel to the direction of the magnetic field?
May 17, 2013

alg
sqrt(3x^2)=-18 check:
May 16, 2013

8need a function rh grade math
a 154 lb person burns 420 calories per hr riding an exercise bike at 15 mph. Need a function rule to represent the total calories burned over time.
May 14, 2013

math (2nd Try)
A salesman gets paid on commission, and his commission is based on how many units he sells during the month. If the salesman sells \$1500 worth of units or less, he makes a flat commission of \$900 plus 10% of the sale. If he sells more than \$1500 worth of units, he makes an ...
May 13, 2013

math
New photo imaging techniques on computers allow artists to distort an image from its original shape. Figure 1 is a square image (X x X). Figure 2 is stretched 4 units wider and shrunk 4 units shorter than figure 1. (x+4)(X-4). How many square units greater is the area of ...
May 10, 2013

math
A ball is kicked from ground level into the air. Its height, y, in feet after x seconds can be represented by the equation y=40x - 16x^2. What is the total elapsed time, in seconds, from the time the ball is kicked until it reaches ground level again? I used the quadratic ...
May 10, 2013

math
Solve for the variable h: 5r - 6h = m Is it h = 5/6m +r If not, please explain. Thanks
May 10, 2013

math
What is the result when correctly solving the formula for the variable w when the formula for the perimeter P of a rectangle is P=2l + 2w? Is it w = (p-2l)/2 If not, please explain. Thanks
May 10, 2013

math
Ursula spent a total of \$52.34 on two new outfits. She bought two shirt for \$12.99, a pair of pants for \$18.50, and a skirt. If the sales tax was 7.5%, what was the cost of the skirt? Please solve and exlain. Thanks
May 10, 2013

math
A salesman gets paid on commission, and his commission is based on how many units he sells during the month. If the salesman sells \$1500 worth of units or less, he makes a flat commission of \$900 plus 10% of the sale. If he sells more than \$1500 worth of units, he makes an ...
May 10, 2013

Alg 1
Solve for the variable h: 5r - 6h = m Is h=5/6m +r Correct?
May 9, 2013

Alg 1
The formula for the perimeter P of a rectangle is P=2l +2w. What is the result when correctly solving the formula for the variable w?
May 9, 2013

Alg 1
Issa is driving to the airport to catch a flight to miami, and her arrival depoends on traffic. If the traffic is light, then she can drive 60 mph and arrive at the airport 1 hour early. If traffic is heavy, she can drive 35 mph and arrive at the airport on time. The equation ...
May 9, 2013

Algebra 1
Emily rows six miles downstream in 1 hour and her friend Ashley,rowing 1 mile per hour faster,completes the return trip in 2 hours. 1.Find the speed of the current(c) and each girls rowing speed. 2.If Emily and Ashley were rowing separately,who would complete their trip first ...
May 7, 2013

Physics
a magnetic rail gun is constucted to give a space vehicle its intial launch velocity, thereby reducing the amount of fuel the vehicle has to carry. it consist of two very long parallel rails across which is positioned a large current carrying crossbar 7.65 m long. The crossbar...
May 4, 2013

Math
Use Excel’s PMT function to calculate the monthly mortgage payment
May 2, 2013

math
Alyssa is enrolled in a public-speaking class. Each week she is required to give a speech of greater length than the speech she gave the week before. The table below show the length of several of her speeches: WK #/Length of Speech (seconds) 3/150, 4/180, 5/210, 6/240 If this ...
April 29, 2013

Alg 1
Diana is driving 182 miles to Orlando for a math convention. She has already driven x miles of th trip. If Diana drives below 70 miles per hour for the remainder of th trip, which inequality best represents the amount of time in hours, t, that is will take her to complete the ...
April 29, 2013

algebra
April 29, 2013

physics
what pressure (in atm) would be exerted by 76g of fluorine gas in a 1.5 litre vessel at -37 degrees Celsius?
April 26, 2013

Algebra
What is the maxima and minima of a parobola?
April 22, 2013

Math
Ms Perez owns 2 properties in different towns. The 1st property is assessed at \$125,000 and has a tax rate of \$6.35 per 1000 dollars. The 2nd property has the same assessed value, but is taxed at the rate of \$0.00587 per dollar. Derive the solution to the total tax obligation ...
April 19, 2013

Probability
If 5 juniors and 4 seniors apply for a job at a school which has 2 openings, what is the probability that 1 junior and 1 senior will be randomly chosen for the job.
April 19, 2013

Alg 1
If y = 1, then (x + 5) times y = x + 5 Which property does it apply to? Cumutative Property of addition? My choices are: Inverse Property of Mult. Identity Property of Mult. Associative Property of addition Cummutative Property of addition.
April 16, 2013

Alg 1
Michael takes 90 min to type 5850 words. If he increases his typing speed by 5 words/min. How many minutes will he take to type 10,500 words? Is it 150 minutes?
April 16, 2013

Alg 1
It is copied correctly. My choices are: 6/5 sqrt11 + 6/5 5/6 sqrt11 + 6/5 6/5 sqrt11 - 6/5 5/6 sqrt11 - 6/5
April 16, 2013

Alg 1
Solve the proportion: 4/x = (radical sign over 11, not -1) 11 - 1/3 Please solve and explain. My answer does not match any of my choices.
April 16, 2013

Alg 1
Why multiply it by 200? My answer choices are: 18.07 ft 35.96 ft 9.04 ft 71.93 ft
April 16, 2013

Alg 1
Landon is standing in a hole that is 6.5 ft deep. He throws a rock and it goes up into the air, out of the hole, and then lands on the ground above. The path of the rock can be modeled by the equation y = -0.005x^2 + 0.45x - 6.5, where x is the horizontal distance of the rock...
April 16, 2013

alg 1
Thanks Steve, you are always so helpful. There was no error data. The only thing I did not type from the problem was: (The measurements are accurate to the nearest inch). This was typed over the answer choices.
April 16, 2013

alg 1
Find the percent error in calculating the volume of the prism. V=(bw)(h) v=11 x 8 (7) V=616 my choices were: 19% 10% 119% 83% I'm not sure what it means to find the percent error. Please explain. Thanks.
April 16, 2013

Alg 1
What are the approximate solutions of 2x^2 -x + 10 = 0 In working this, I came up with a negative (-79) under the radical sign. Can I take the sq rt of a negative? my choices are: -2, 2.5 -1.97, 2.47 -2.5, 2 No solution I think it is no solution. Is this correct? If not, ...
April 15, 2013

Alg 1
Reasoning: The equation 3x^2 + bx + 3 = 0 has one real solution. What must be true about b? I think it is: b must be the same as -4(a)(c). What are your thoughts?
April 15, 2013

Alg 1
The equation is: -w^2 +75w - 1200 the neg sign was so close to the = sign above. Sorry about that.
April 15, 2013

Alg 1
The quadratic formula and the discriminat. The daily production of a company is modeled by the function p=-w^2 + 75w - 1200. The daily production, p, is dependent on the number of workers w, present. If the break-even point is when p=0, what are the least and greatest number ...
April 15, 2013

Alg 1
A box shaped like a rectangular prism has a height of 17 in. and a volume of 2720 in^3. The length is 4 inches greater than twice the width. What is the width of the box? Please solve and explain what I need to do. The choices are: -10 8 20 40
April 14, 2013

Alg 1
The rectangular has an area of 5400 cm^2. What is the value of w? 5400 = (w)(2w - 30) 5400 = 2w^2 - 30 w 5400 = 2w(w - 15) Now I am stuck. My choices are: -45 cm 45 cm 60 cm 90 cm What do I need to do next to get the correct answer? Thanks.
April 14, 2013

Alg 1
Completing the square: Which of the following is a solution x^2 + 14x + 112 = 0? If necessary round to the nearest hundredth. x= -0.24 x= -4.24 x= 4.24 no solution I worked it and got neither of the answers. I got x= 0.9 and x=-14.9. Where did I go wrong? Thanks
April 14, 2013

Alg 1
Completing the square: Find the value of c such that each expression is a perfect-square trinomial. p^2 - 11p + c Is the answer 30.25? If not, please explain. Thanks
April 13, 2013

Alg 1
That two consecutive numbers that multiply and equal 42 is 6x7. 6 + 1+7
April 13, 2013

Alg 1
The product of two consecutive integers, n and n+1, is 42. What is the positive integer that satisfies the situation? Is it 6 x 7?
April 13, 2013

Alg 1
A triangular-shaped wall has a base of 2x+4 and a height of x+3. The area of the triangle is 56 in^2. What is the value of "x"?
April 13, 2013

Al
Factoring to solve quadratic equations: Find the value of x as it relates to the triangle. Area = 600 cm^2 There is a large triangle that is divided by a 90 degree angle in the middle. That 90 degree angle line is "x" and the complete bottom of the large triangle is...
April 13, 2013

PHYSICS
Bricks have a thickness of 12 cm, if an external wall of the house measures 10 mx 15m, calculate the rate of heat exchange through this wall if the inside temperature is 200C and the outside temperature is 50C.
April 10, 2013

Alg 1
Factoring to solve quadratic equations: Use the Zero-Product Property to solve each equation. Write your solution in roster form: The volume of a storage tub shaped like a rectangular prism is 24 ft^3. The height of the tub is 3 feet. The width is w feet and the length is w+...
April 8, 2013

Alg 1
The length of a rectangular prism is four times the width. The height of the prism is 8 ft. If the volume of the prism is 160 ft^3, what is the width of the prism? Round to the nearest tenth of a foot. Please solve and explain. Thanks
April 6, 2013

Alg 1
Solving quadratic equations: What is the value of "b" in the triangle where one part of the right angle is "3b" and the other part of the right angle is "b". The area inside is 24 in^2. Please solve and explain. Thanks
April 6, 2013

Alg 1
Solving quadratic equations: What is the radius of the largest circular quilt that can be made with an area less than or equal to 70 ft^2? Round your answer to the nearest tenth of a foot if necessary. Please solve and explain. Thanks
April 6, 2013

science
What may be some long-term effects of human interactions with the oceanic environments?
April 5, 2013

math
The square yard you are mowing has an area of 9600 ft^2. What is the side length of the yard? Round your answer to the nearest tenth of a foot if necessary. Please solve and explain
April 5, 2013

Chem HW!! Difficult! HELP!
Urea (H2NCONH2) is used extensively as a nitrogen source in fertilizers. It is produced commercially from the reaction of ammonia and carbon dioxide. 2 NH3(g) + CO2(g) ---Heat pressure---> H2NCONH2(s) + H2O(g) Ammonia gas at 223°C and 90. atm flows into a reactor at a ...
April 5, 2013

Alg 1
A baseball player hit a ball with an upward velocity of 46 ft/s. Its height h is feet after t seconds is given by the function h = -16t^2 + 46t + 6. What is the maximum height the ball reaches? How long will it take the baseball to reach the maximum height? How long does it ...
April 4, 2013

alg 1
Quadratic graphs and their properties: Identify the domain and range of each function: y = 4x^2 - 3 I have no idea how to find the range and domain. Would you please explain in detail how I can determine the domain and range in the quadratic problems?
April 4, 2013

STAT
A population has a standard deviation ó of 23 units. (Give your answers correct to two decimal places.) (a) Find the standard error for the mean if n = 11. (b) Find the standard error for the mean if n = 41. (c) Find the standard error for the mean if n = 85.
April 3, 2013

math
A diagram shows the design of the 12 in quilt (12" x 12") block that a quilter is sewing. What are the dimensions of each triangle in the quilt block? What are the dimensions of each triangle to the nearest tenth of an inch?
April 3, 2013

Alg 1
A golden rectangle is 32 cm long. The ratio of length to width is (1 + sq rt 5)/2. What is the width of the rectangle in simplest radical form? Please solve and explain. Thanks.
April 3, 2013

Alg 1
Find the exact solution for each equaton. Find the approximate solution to the nearest tenth. 3 sq rt 3/sq rt 1 + sq rt 1 = x/sq rt 3 Please solve and explain. Thanks
April 3, 2013

math
Operations with radical expressions: Simplify each quotient. -3/sq rt 2 + sq rt 5
April 3, 2013

Alg 1
Find the exact solution for each equation. Find the approximate solution to the nearest tenth. 5 sq rt 2/ sq rt 2 -1 = x / sq rt 2 Please explain in detail how to work this. I am really confused. Thanks
April 3, 2013

Alg 1
Operations with radical expressions: Simplify each quotient 7/sq rt 2 - sq rt 3 Please solve and explain how you did it. What do you do when the denominator is a negative?
April 3, 2013

Alg 1
An area rug is shaped like a golden rectangle. Its length is 8 ft. What is the rug's width? Write your answer in simplified radical form and rounded to the nearest tenth of a foot. Please explain how to work this. Thanks.
April 2, 2013

Alg 1
Thanks you all so much!
April 2, 2013

Alg 1
Would you please show me how you arrived at the answer "D." I don't know how to set up the problem to get the answer. Thanks
April 2, 2013

Alg 1
Simplifying Radicals A gardener is mowing a 20-yd-by-40 yd rectangular pasture using a diagonal pattern. He mows from one corner of the pasture to the cxorner diagonally opposite. What is the length of this pass with the mower? Give your answer in simplified form. My answer ...
April 2, 2013