Math CentralQuandaries & Queries


Question from Adam:

What does

(a-b)/b = c

represent when c is a percentage?

Hi Adam,

a - b is the difference between a and b or the change in going from b to a. I am thinking of a being larger than b so that this quantity has value b and then increases to value a, hence the increase is a - b. For example consider b = 12 and a = 18 then a - b = 6. Dividing by b gives a measure of this increase relative to the value of b. In this case (a - b)/b = 6/12 = 1/2, or said as a percentage, 50%. This is the quantity we call percentage increase or percentage change.

For example look at this question about car sales.


About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS