Check Your Skills Answer Key

  1. 0.87

    Shift the decimal two places to the left and remove the percent symbol:
    87% becomes 0.87

  2. Divide the percent figure by 100, then simplify:
    30% becomes 30/100, which reduces to 3/10

  1. 37%

    Shift the decimal two places to the right and add a percent sign:
    0.37 becomes 37%.

  2. Notice that the decimal has two digits to the right of the decimal place:
    0.25 is 25 hundredths, so it becomes 25/100, which reduces to 1/4.

  1. 0.6

    Divide the numerator by the denominator:
    3/5 is 3 ÷ 5 = 0.6

  2. 37.5%

    Divide the numerator by the denominator, shift the decimal two places to the right, and add a percent sign:

    Step 1: 3/8 is 3 ÷ 8 = 0.375
    Step 2: 0.375 = 37.5%

  1. x = 0.6y

    x = 60% (y)

    x = 0.6y

  3. y = 0.25x

    Let x equal the number in question:

    y = 25% (x)

    y = 0.25(x)

  1. 10 gallons

    Let x be the capacity of the water drum. If the drum is 1/4 full, and 30 gallons would make it full, then 30 = (1 − 1/4)x, which means:

    Divide both sides by 3/4. This is equivalent to multiplying by 4/3:

    If the total capacity is 40 gallons and the drum is 1/4 full, then the drum currently contains 1/4 × 40, or 10 gallons.