1. Math

    In January, the price of a kilogram of potatoes at Supermarket X was $3.20. In May, a kilogram of the same type of potatoes cost $2.99. Find the percentage decrease in price. Express your answer correct to 1 decimal place.
  2. math

    You sell and service vacuum cleaners. Your price on a particular model is $125. However, to get a service contract, you offer to sell it for $115. How much discount are you giving as a percentage of price (to the nearest tenth)?
  3. statistics

    The test scores of students in a class test have a mean of 65 and with a standard deviation of 8. What is the probable percentage of students scored more than 70? Please check work 70-65/8 = .625 = .2357 = 1.-.2357 = .7643 ANSWER 76% ????
  4. Chemistry Help!!!!

    for each of the following pairs of elements, give the correct molecular formula, explain how you arrived at this answer( you may use the Bohr model notation, or the orbital model notation, or explain linguistically) and note whether the bonding is covalent
  5. Math

    If you have a graph with the x-axis as the days of the month, and the y-axis as stock price.... Then, how to do you figure out the percentage drop in stock price for each week?
  6. math

    in a distribution of 160 values with a mean of 72,at least 120 fall within the interval 67-77. approximately what percentage of values should fall in the interval 62-82? use chebyshev's formula.
  7. math

    What was the percentage increase in motor vehicle production in motor vehicle production in countries outside the united states from 1950 to 1997?
  8. chemistry lab

    If a portion of your aspirin sample had broken down, how would that effect the total amount of base used? What would the effect be on the percentage of aspirin in your sample?
  9. maths

    A solution whose volume is 80% liters is made up of 40% of water and 60% of alcohol,When x liters of water is added the percentage of alcohol drops to 40% Find X
  10. chemistry

    The percentage yield for the reaction PCL3+Cl2-->PCL5 is 83.2%. What mass of PCL5 is expected from the reaction of 73.7g of PCL3 with excess chlorine?
  11. mathematics

    There are thrice as many girls as boys at a school. If 35% of the girls and 45% of the boys have already completed their holiday project, what percentage of the learners still needs to complete their project?
  12. math

    If 50ml of a 7.5% (w/v) sodium bicarbonate injection are added to 500ml of a5% dextrose injection , what is the percentage strength (w/v)of sodium bicarbonate in product?
  13. MATHEMATICS

    There are thrice as many girls as boys at a school. If 35% of the girls and 45% of the boys have already completed their holiday project, what percentage of the learners still needs to complete their project?
  14. statistics

    I need to see the steps to figuring out this problem. 270 patients were given a placebo of those 270, 19 had headaches. What percentage of this placebo group reported headaches?
  15. Statistics

    Assuming that the heights of college women are normally distributed with mean 62 inches and standard deviation 3.5 inches, what percentage of women are between 58.5 inches and 72.5 inches? (Points: 5) 34.1% 84.0% 15.7% 13.6% 97.6%
  16. finance

    A manufacturing company issues a bond with a 100,000 face value and a coupon rate of 7%. If the bond has a life of 30 years, pays annual coupons, and the yield to maturity is 6.8%, what percentage of the bond's price is the present value of the face value?
  17. statistics

    Solve the problem. The lifetime of a new brand of light bulb can be described by a Normal model with a mean of 2000 hours and a standard deviation of 250 hours. Find the percentage of light bulbs that will last more than 2600 hours. A.) 100% B.) 5% C.)
  18. chemistry

    a 5.0 dm3 sample of oxygen at a pressure of 200 kPa and 2.0 dm3 sample of nitrogen at a pressure of 500 kPa are introduced into a 2.5 dm3 vessel. what is the total pressure in the vessel?
  19. math

    Your station charges $16.50 for a lubrication job. As a promotion you sell six coupons for lubrication jobs for $90. What percentage discount are you offering for customers who purchase the 6-coupon lube book? Discount (to the nearest tenth) = % The answer
  20. economics

    A speculator sells a stock short for $50 a share. The company pays a $2 annual cash dividend. After a year has passed the seller cover a short position of $42. What is the percentage return on the position (excluding the impact of any interest expense and
  21. Finance

    . Suppose the December CBOT Treasury bond futures contract has a quoted price of 80-07. If annual interest rates go up by 1.00 percentage point, what is the gain or loss on the futures contract? (Assume a $1,000 par value, and round to the nearest whole
  22. Statistics

    The Arcade shack is a manufacturing plant located in San Diego where 800 factory workers are employed. The personnel department selected 36 factory employees at random for the statistical study. construct a 95% interval for the percentage of males in the
  23. Chemistry

    NH3(g) + 2O2 (g) = HNO3 (aq) + H2O (l) How do I calculate the oxidation states of Nitrogen and figure out if it is reduced, oxidized or neither? My answer is below. I am not sure if I am figuring it right. Please advise. NH3(g) + 2O2 (g) = HNO3 (aq) + H2O
  24. Math

    Consider the weighted voting system [75: 31, 29, 23, 16, 8, 7]. Find each: a. The total number of players b. The total number of votes c. The weight of P3 d. The minimum percentage of the votes needed to pass a motion 9rounded to the next whole percent)
  25. Trigonometry

    In 2010, the population of a country was 70 million and growing at a rate of 1.9% per year. assuming the percentage growth rate remains constant express the population P, as a function of t, the number of years after 2010.
  26. Physics

    A 50 g ball of clay traveling at speed v0 hits and sticks to a 1.0 kg block sitting at rest on a frictionless surface. A) What is the speed of the block after the collision? B) What percentage of the ball's initial energy is "lost"?
  27. chemistry

    i'm having a hard time for my chemistry project an my topic on titration and my topic is to determine the mass percentage of iron in steel wool and i can not get as much information on the steps to follows how to create the titration and equipment needed
  28. physics

    A coal-fired electrical generating plant has an efficiency of 38%. The temperature of the steam leaving the boiler is 550 °C. What percentage of the maximum possible efficiency does this plant obtain? (Assume the temperature of the environment is 20 °C)
  29. Chemistry

    a sample of a compound with a mass of 0.4168g is extracted from a plant. Decompostion of this sample produces 0.1667g of carbon, 0.2223g oxygen, and the remainder is hydrogen. What is the percentage compostion (by mass) of the compound?
  30. chemistry

    In the chlorine titration of a solution prepared by the dissolution of 0.2110 g of commercial hypochlorite was spent 19.50 ML of sodium thiosulphate solution 0.1002 mol/L. Calculate the percentage of chlorine (35.45 g/mol) in this sample
  31. Statistics

    We are working on pivot tables with grouping. I have no trouble creating a table with variables and totals however, I cannot figure out how I can include Relative Frequencies and Percentage frequencies in the same pivot table - as shown in the book. Thanks
  32. Physics

    a) The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/day for males. Express this quantity in ?g/s. Express this quantity in b) For adults, the RDA of the amino acid lysine is 12 mg per kg of body weight. How many grams per day
  33. 12 Chemistry

    What is the molar enthalpy of combustion of magnesium? This was the lab question that I was asked to find after performing a lab based on Hess' law. I can't find anywhere in my notes how to calculate this, and the text book doesn't explain their steps
  34. statistics

    A company produces batteries whose lifetimes are normally distributed with a mean of 100 hours. It is known that 90% of the batteries last at least 40 hours. (i). Estimate the standard deviation lifetime. (3 marks) (ii). What percentage of batteries will
  35. College General Biology

    A man who is a non-tongue roller (t) marries a woman tongue roller (T) whose father was a non-tongue roller (t) - what would the expected genotype and phenotype percentage for their offspring?
  36. statistics

    If a major Internet store wants to estimate the percentage of adult Internet shoppers in order to determine the maximum impact of Internet shoppers on its sales, what amount of the shoppers should be used as a sample?
  37. Chemistry

    Graham's Law predicts that the ratio of the rate of effusion of gas X to the rate of gas Y equals the square root of the INVERTED ratio of their molar masses: Rate of X/Rate of Y = SQRT(My/Mx) What is the ratio of rate of effusion of Helium to Nitrogen
  38. math

    When managing a business, it is important to take inventory of where your money is spent. You have a monthly budget of $5,000. Refer to the table below and answer the questions that follow. Round your answers to the nearest tenth of a percent. Category
  39. Chemistry 101

    10.0 grams of nitrogen is reacted with 10.0 grams of the element phosphorus under certain conditions to yield trinitrogen diphosphide. Answer these questions. 1). Write a balanced equation. 2). which reactant is limiting? In excess? 3). Theoretically, how
  40. chemistry

    A mixture og gases has a total pressure off 28.3 atm, it is made of: 5.8 atm of hydrogen gas, 7.2 atm of nitrogen gas, 3.5 atm of oxygen gas and some amount of methane. What is the pressure of methane? what is the pressure of methane in kPa?
  41. Chemistry. Please help!

    A 20.29 g sample of impure MgCO3 is completely decomposed at 1000oC in previously evacuated 2.0 L reaction vessel. After the reaction was complete the solid residue had a mass of 15.9 g. Assume that only MgCO3 could produce gas CO2 what percent of original
  42. chemistry

    A 12.42 gram sample of a mixture of NaCl and CaCl2 is dissolved in water and all the chloride is precipitated as AgCl. If the AgCl precipitate has a mass of 31.70 grams. How do I find the mass percentage of each component in the original mixture?
  43. Chemistry

    a silver coin has a mass of 2.50g and is analysed for silver by dissolving in dilute nitric acid, and precipitating silver as solid AgCl and weighing this. if the percipitat weighs 2.99g what percentage of silver is the coin?
  44. chemistry

    25 ml of milk were titrated with a 0.124M KOH solution of potassium hydroxide. If 4.5 ml of KOH solution were required to reach the titration endpoint, with a percentage (% w / v) lactic acid present in the milk? (MM = 90.08g / mol)
  45. math plz help !!!

    plz help me I'm desperate!!! Jerry mixes the letters F,P,M,M,M,F,P and J thorough. Without looking Amanda draws one letter. Expressed as a fraction, decimal and percentage. What is the probability that J will NOT be the letter Amanda selects? A.7/8, 0.875,
  46. statistics

    A group of 50 teachers and school administrators attended a convention. If any two persons are picked at random, at least one of the two would be a teacher. From this information, what percentage of the people at the convention were teachers? Could someone
  47. Chemistry

    A 3.23 gram sample of a sodium bicarbonate mixture was reacted with excess acid. 48.52 mL of the evolved gas was collected of the water at .930 atm. and 23.0 degrees C. What is the percentage of sodium bicarbonate in the original mixture?
  48. Stats

    At a major International Airport, 0.49 of the flights arrive on time. A sample of 12 flights is studied. What is the probability that more than 3 of them arrived on time? Write only a number as your answer. Round to 2 decimal places (for example 0.24). Do
  49. Chemistry

    When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage
  50. Chemistry

    When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage
  51. Math

    The edge of a cube was found to have a length of 50 cm with a possible error in measurement of 0.1 cm. Based on the measurement, you determine that the volume is 125,000 cm3. Use tangent line approximation to estimate the percentage error in volume.
  52. statistics

    Assume that a set of test scores is normally distributed with a mean of 100 and a standard devaiton of 20. Use the 68-95-99.7 rule to find the following quantities: a. percentages of scores less than 100 b. relative frequency of scores less than 120
  53. Algebra

    The selling prices of houses in a city during one year were normally ditributed with a mean of $259,000 and a standard deviation of $15,000. Which of the following is closest to the percentage of the homes that had a selling Price between $244,000 and
  54. Chemistry

    A 1.00 g sample of limestone is allowed to react with 100 cm^3 of 0.200 mol/dm^3 HCl. The excess acid required 24.8 cm^3 of 0.100 mol/dm^3 NaOH solution. Calculate the percentage of calcium carbonate in the limestone
  55. Managerial Finance

    East Coast Yachts uses a small percentage of preferred stock as a source of financing. In calculating the ratios for the company, should preferred stock be included as part of the company’s total equity
  56. Chemistry

    a silver coin has a mass of 2.50g and is analysed for silver by dissolving in dilute nitric acid, and precipitating silver as solid AgCl and weighing this. if the percipitate weighs 2.99g what percentage of silver is in the coin?
  57. statistics

    It is estimated that amounts of money spent on gasoline by customers at their gas stations follows a normal distribution witha standard deviation of $3. It was also found that 10% of all customers spent more than $25. What percentage of customers spent
  58. Chemistry

    A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by O3(g)+NO(g) --> O2(g)+NO2(g) The rate law for this reaction is: rate=k[O3][NO] Given that k = 2.87 × 106 M–1·s–1 at a certain temperature,
  59. Chemistry

    A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by O3(g)+NO(g) --> O2(g)+NO2(g) The rate law for this reaction is: rate=k[O3][NO] Given that k = 2.87 × 106 M–1·s–1 at a certain temperature,
  60. Algebra

    A company reported that it made a profit of 8% as a percentage of sales and that its sales revenue was $25,000. How much profit did the company make?
  61. math

    Laura insured her car for $12,000. When it was damaged she got $8,000 from the insurance company. What percentage of the insured amount did Laura get
  62. math

    if 8 men can do a job in days, what is the percentage increase in number of days required to do the job when 2 men are released? not just an answer please. A.16 2/3% B.25% C. 33 1/3% D.40% E.48%
  63. Chem

    Determine the concentration of a dioxin solution whose percent absorbance is 0.40% This is the resulting: Absorbance Dioxin 0.64 5.5 0.76 6.3 1.0 8.0 But why can't I figure out the concentration whose percentage is .40%?
  64. Math

    there are 50 animals on a farm,24% of them are pigs, 30% are cows and the remaining are sheep. what is the percentage of the total number of cows and pigs to that of the sheep?
  65. math

    jenny needs to make a total of 85 deliveries this week. so far she has delivered 34 of them. what percentage of her total deliveries has jenny completed? how do u figure this out please
  66. Chemistry

    I have to find the percentage of error. The accepted value is 11.35, while the value I got is 2.564. I got 2.564-11.35/11.35, and got a negative answer. Can percentages of error be negative? Thanks-Coralie.
  67. percentage

    in an election between two candidates one got 55% of the valid votes. 20% of the votes are invalid. if the total votes are 500 what is the percent of total votes that the other person got
  68. math

    If a basketball player missed 41 free throws out of 100, what fraction and what percentage of free throws did the player make?
  69. chemistry

    The polarogram for 20ml solution that was 3.65 x 10^-3 M in cadmium (Cd2+) gave a wave for that ion with a diffusion current of 31.3microampere. Calculate the percentage change in concentration of the solution is the current in the limiting current region
  70. Chemistry

    Excess lead (II) nitrate solution is added to 1.30 g of zinc powder and the mixture is stirred. When the reaction is finished the lead formed is filtered, dried and weighted. It has a mass of 3.31 g. What is the percentage yield of the lead? Pb(NO3)2 + Zn
  71. Math

    Could someone tell me if I got these problems right. A man used 1 pt. 9fl oz. of cleaner, then he used 2 pt 10 fl oz. out of a 3 qt. bottle. How much cleaner is left? = 1 pt. 13 floz The United States emitted 19.5 million t of nitrogen oxides(NO) into the
  72. Chemistry 101

    This is the question 10.0 grams of nitrogen is reacted with 10.0 grams of the element phosphorus under certain conditions to yield trinitrogen diphosphide. Answer these questions. 1). Write a balanced equation. 2). which reactant is limiting? In excess?
  73. chemistry

    a chemist puts 6 moles of nitrogen gas and 7 moles hydrogen gas into an evacuated 1 liter container. The system reaches equilibrium at a certain temperature according to the process outlined above. when the system is at equilibrium the chemist determines
  74. Elementary Statistics

    "Scores on the Wechsler IQ test approximate a normal curve with a mean of 100 and a standard deviation of 15. b. What percentage of IQ scores are below 74?" I've been working at this for a while now, but when I solve for the z-score, I keep getting a
  75. organic chemistry

    Calculate the weight of benzene codistilled with each gram of water and the percentage composition of the vapor produced during a steam distillation. The boiling point of the mixture is 69.4°C. The vapor pressure of water at 69.4°C is 227.7 mmHg. Compare
  76. chemistry

    We can determine the content (%) of calcium in milk through complexometric analysis by titration with EDTA. If we weigh 0.50 g of milk powder and titrate with EDTA 0.010 mol/L. What percentage of Ca2+does the milk if expended EDTA was 13.6 ml?
  77. Chemistry

    A solution contains H2O2 in water. Complete decomposition of the H2O2 in 170 g of this solution yields 5.6 L of O2(g), measured at 0 oC and 101.325 kPa. What is the percentage by mass of H2O2 in this solution? Choose the closest answer. A 10% B 20% C 5.0%
  78. math

    Suppose x is a random variable with mean and standard deviation. If a large number of trials is observed, at least what percentage of these values is expected to lie beween mean-2(standard deviation) and mean + 2(standard deviation) could someone help me
  79. math

    if there are 28 students in a class and there are 13 girls, what percentage of the class is girls?
  80. math

    If you have a class of 45 students and 15 are boys what is the percentage of boys in the class
  81. math

    Of all the species in the world, 4 out of every 5 are insects. What percentage of species are insects?
  82. Math

    A class has 30 boys and 25 girls. what is the percentage of boys in the class?
  83. mathematics

    If 24 out of 30 pupils in a class are present, what percentage of the pupils are present
  84. Math

    There are 25 students. Yesterday, 6 of them were absent. What percentage of the students were absent?
  85. Chemistry

    A 1.0 L ball containing Ar at 5 atm is connected to a 10.0 L ball containing N2 at 2 atm. a) Calculate the partial pressure and mole fractions of argon and nitrogen after the valve is opened and the gases are allowed to mix (they fill the balls on both
  86. physics.

    Rank the following from most to least for the percentage of its volume above the water line: A. Basketball floating in saltwater B. Basketball floating in glycerin C. Basketball floating in gasoline
  87. Chemistry

    The decomposition of ehtane, C_2H_6, is a first-order reaction. It is found that it takes 212seconds to decompose 0.00839M C_2H_6 to 0.00768M. A. How long in minutes will it take to decompose ethane so that 27% remain B. What percentage of ethane is
  88. math

    A (yearly) cash flow stream is x=(-40,10,10,10,10,10,10). The spot rates are (yearly in percentage) s=(5.0,5.3,5.6,5.8,6.0,6.1). Use the discount factors to determine the (net) present value of the stream. (I got a little confused here. Should I 1. use the
  89. math

    A bookseller marks his books at an advance of 69% in actual cost of production.he allows a discount of 15% and also given a copy free for every dozen sold a time.what rate percentage profit does the bookseller make,if books are sold to 12? ( ANS 32.6? )
  90. Chemistry

    A 1.85-g sample of a mixture of KCl and MgCl(subscript 2) is treated with excess AgNO(subscript 3) (aq). If 3.82 grams of AgCl(s) are obtained, then what is the percentage by mass of KCl in the original mixture. Can someone tell me what the balanced
  91. financial management

    I have to do a revenue and expense statement and balance sheet for 2 years I have find the dollar differences and the percentage rate. My mind is a blank I do not remember how to find the percent of financial statements. Is it the same as finding the
  92. accounting

    Pattillo Industries makes a product that sells for $25 a unit. The product has a $5 per unit variable cost and total fixed costs of $9,000. At budgeted sales of 1,000 units, the margin of safety percentage is 45%, 55%, 64%, none of these
  93. Math Lit

    In a school there are 122 grade 8s, 105 grade 9s, 134 grade 10s, 109 grade 11s, 90 grade 12s. Express Each Class as a percentage of the whole school.
  94. physics

    A scuba diver must decompress after a deep dive to allow excess nitrogen to exit safely from his bloodstream. The length of time required for decompression depends on the total change in pressure that the diver experienced. Find this total change in
  95. math

    A person takes out a monthly installment loan of $2000 with an annual percentage rate of 13.0% if the person can afford no more than $70 per month, then which of the following terms are feasible? a) 8 months b ) 12 months c) 18 months d) 24 months e) 36
  96. chemistry calculations

    At 25 deg C, Kc is 5.84x10-3 for the dissociation of dinitrogen tetraoxide to nitrogen dioxide. N2O4(g) ==== 2NO2(g) a) Calculate the equilibrium concentration of both gases when 4.00 grams of N2O4 is placed at 2.00-liter flask at 25 deg C. b) What will be
  97. chemistry

    Copper reacts with nitric acid according to the following reaction: 3 Cu (s) + 8 HNO3 (aq) --> 3 Cu(NO3)2 (aq) + 2 NO (g) + 4 H2O (l) If an pre 1982 copper penny contains 3.10 grams of copper, what volume of 8.00 M nitric acid is required to exactly
  98. Chemistry

    Bacterial digestion is an economical method of sewage treatment. The reaction 5CO2(g) + 55NH4+(aq) + 76O2(g) --bacteria--> C5H7O2N(s)[bacterial tissue] + 54NO2-(aq) + 52H2O(l) + 109H+(aq) is an intermediate step in the conversion of the nitrogen in
  99. chemistry-gases-ppm

    Nitrogen dioxide reacts with water and oxygen in the atmosphere to produce acid rain. 4NO2(g) + 2H2O(g) + O2(g) = 4HNO3(g) Assuming that the temperature and the pressure remain constant, calculate the volume of air at 1 atm, 20 C, necessary to dilute the
  100. Chemistry

    Nitrogen dioxide is one of the components of photochemical smog. a.The energy required to split NO and O from NO2 is 305 KJ/mol. If there are 6.02E23 particles/mol, what is the energy required to do this? (I got 5.07E24) b. What is the maximum wave length