Expert: Abe Mantell - 8/21/2010

Question
Hello:

Is a ratio an inclusive term for a fraction and a rate?

Units of measure accompany the terms of a fraction, as in 60 miles per 1 hour is an example for a rate. Ratios can compare different items. For example a classroom with a ratio of girls to boys as in 16 girls to 4 boys, but this example would not be called a rate. Fractions are usually just one number over another without units and not used to compare something.

I thank you for your reply.

Answer
Fractions often do include units to give them more meaning than just
a unitless ratio.  The example you gave, 60 miles/hr gives a ratio
that has meaning as a rate of change (distance per unit time).
16 girls to 4 boys can be expressed as (16 girls)/(4 boys)
= (4 girls)/(1 boy), which tells us that there are 4 girls per boy
in the class.

I hope this helps.

Abe