GED Mathematical Reasoning TestQuantitative Problem Solving with Rational NumbersMedium

A chemist is preparing a solution. She needs 3/5 of a liter of a chemical. She only has a measuring beaker that measures in milliliters. How many milliliters of the chemical does she need?

  1. A30 mL
  2. B600 mL
  3. C60 mL
  4. D300 mL
Show answer & explanation

Correct answer: B. 600 mL

To convert liters to milliliters, multiply the number of liters by 1000, since 1 liter equals 1000 milliliters. Then, calculate 3/5 of that total.

Why the other options are wrong

  • A. This would be 3/5 of 100 mL, not 1000 mL.
  • C. This would be 3/5 of 200 mL, or if 3/5 was incorrectly converted to 0.06.
  • D. This would be 3/5 of 500 mL, or if the conversion factor was incorrectly used as 100.

Fractional Unit Conversion

To convert a fractional quantity from one unit to another, first determine the conversion factor between the units, then multiply the fraction by this factor.

  • Identify the starting unit and target unit.
  • Determine the conversion factor (e.g., 1 L = 1000 mL).
  • Multiply the fractional quantity by the conversion factor.
  • Perform the multiplication and simplify the result.

Memory trick: Fractional amounts, convert with care, then measure with flair!

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