How to Write a Ratio As a Unit Rate
A unit rate is the ratio of two quantities when there is exactly 1 of the second quantity. Unit rates are the standard for measuring values such as speed (miles per hour) and pressure (pounds per square inch). When calculating rates, however, it is common that the measured amount of the second quantity is not exactly one. Use long division to convert this rate to a unit rate.
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Instructions
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Set up a long division equation with the numerator of the ratio on the inside of the division symbol and the denominator of the ratio on the outside of the symbol. For example, if the ratio of white mice to gray mice is 21/9, write 21 inside the symbol and 9 outside the symbol.
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2
Perform long division by finding the number of times the denominator goes into the numerator and subtracting the product of this number and the denominator from the numerator to get the remainder. In the above example, 9 goes into 21 twice with a remainder of 3 because 21 - 9*2 = 3, so the answer is 2 remainder 3.
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3
Use long division to rewrite the remainder as a decimal by writing a zero after the remainder, calculating the number of times that the denominator goes into this number and writing this number after the decimal point in the answer. In the above example, write a zero after the 3 to get 30. 9 goes into 30 three times, so rewrite the answer as 3.3
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Write the answer from Step 3 as the numerator of the unit rate and 1 as the denominator. In the example, the unit rate 3.3/1 is the equivalent unit rate for 21 white mice to 9 gray mice.
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References
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