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Decimals Word Problems Practice Questions Set 3 (page 2)

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Updated on Sep 26, 2011

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  1. d. Use the formula d = rt (distance = rate × time). Substitute 117 miles for d. Substitute 2.25 hours for t and solve for r.
  2. The rate is 52 miles per hour.

  3. a. Subtract 0.25 from 3.5; 3.5 – 0.25 = 3.25 feet.
  4. d. Multiply 6.5 by 110; 6.5 × 110 = 715 bricks.
  5. b. Substitute 6 for r in the formula A = πr2 and solve for A.
  6. A = (3.14)(62)

    A = (3.14)(36)

    A = 113.04

    The area of the circle is 113.04 square inches.

    A common mistake in this problem is to say that 62 is 12. This is NOT true; 62 means 6 × 6 which equals 36.

  7. a. Multiply 54 by $0.06 to find the total cost; 54 × $0.06 = $3.24.
  8. d. Multiply 13.5 by 4 to find the number of copies made; 13.5 × 4 = 54 copies.
  9. b. Three tenths of a cent can be written as 0.3¢, or changed to dollars by moving the decimal point two places to the left, $0.003. If $0.003 is added to $2.349, the answer is $2.352.
  10. a. $1.45 is rounded to $1.00. You are rounding to the ones place, so look at the place to the right (the tenths place) to decide whether to round up or stay the same. Since 4 is less than 5, the 1 stays the same and the places after the 1 become zero.
  11. d. The insulation surrounds the whole pipe. If the diameter is 2.5 inches, the insulation will add 0.05 inches on both sides of the diameter. See the diagram below; 2.5 + 0.5 + 0.5 = 3.5 inches.
  12. Decimals

  13. c. To find the cost per ounce, divide the cost by the number of ounces; $3.20 ÷ 64 = $0.05 per ounce.
  14. d. First, find the number of hours George worked. From 7:00 a.m. to 3:30 p.m. is 8 hours. Take away his hour break and he works 7 hours. To find what George is paid, multiply the hours worked, 7.75 (changed from the fraction), by the pay per hour, $10.50; 7.75 × $10.50 = $81.375. The directions say to round to the nearest cent. Therefore, the answer is $81.38.
  15. a. Since the tank was full on Monday, whatever it takes to fill the tank is the amount of gas that she has used. Therefore, she has used 12.4 gallons of gas. Next, find the number of miles Marci traveled by subtracting Monday's odometer reading from Friday's odometer reading; 32,659.7 – 32,461.3 = 198.4 miles. Divide the miles driven by the gas used to find the miles per gallon; 198.4 ÷ 12.4 = 16 miles per gallon.
  16. d. Divide the $20 by $4.25 to find the number of calculators she can buy; $20 ÷ $4.50 = 4.405. She can buy 4 calculators. She doesn't have enough to buy a fifth calculator. This means that she has spent $17 on calculators because $4.25 × 4 = $17. To find how much she has left, subtract $20 and $17. The answer is $3.
  17. b. Place the smallest number in the largest place value and work your way down, putting the digits in ascending order. Thus, the answer is 0.3568.
  18. c. Zeros can be added to the end (right) of the decimal portion of a number without changing the value of the number; 12.0870 is equivalent to 12.087—a 0 has just been added to the end of the number.
  19. d. When multiplying by a number less than 1, you get a product that is less than the number you started with. Multiplying by a number greater than 1 gives you a larger number than you started with. Therefore, multiplying by 1.0002 will yield a number larger than the one you started with.
  20. b. First, figure out the cost of the fence by multiplying the number of feet of fence by $3.25; 350 × $3.25 = $1,137.50. Next, find the cost of the labor by multiplying the hours of labor by $15.75; 6 × $15.75 = $94.50. Add the two costs together to find what Kelly owes Fabulous Fence; $1,137.50 + $94.50 = $1,232.
  21. c. Find the amount of rain that has fallen so far; 2.6 + 3.4 + 2.1 = 8.1 cm. Find the difference between this amount and the average rainfall by subtracting; 9.7 – 8.1 = 1.6 cm.
  22. a. It is moved three places to the right. When multiplying by multiples of 10, the decimal point is moved to the right according to the number of zeros. For example: Multiply by 10 and move the decimal one place; multiply by 100 and move the decimal two places.
  23. a. Divide the cost of the turkey by the weight; $6.90 ÷ 1.5 = $4.60.
  24. d. Multiply the price per piece by the number of pieces; 14.9 × 1,500 = 22,350 cents. Change the cents into dollars by dividing by 100 (move the decimal point two places to the left); 22,350 cents = $223.50.
  25. b. It will move one place to the left. When dividing by multiples of 10, the decimal point is moved to the left according to the number of zeros. For example: Divide by 100 and move the decimal two places; divide by 1,000 and move the decimal three places.

More practice problems on decimals word problems can be found at:

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