A proportion is a statement that two ratios are equal.
For example, if we say that 3 pencils cost 60 cents. Then 6 pencils will cost 120 cents. Notice that they form the same ratio of 3 : 60 = 6: 120? When they form the same ratio, we say that the number of pencils is proportional to the cost.
Typically, we do such questions this way:
Example Questions on Proportion
Jane reads 20 pages of a book in 4 hours. How many pages can she read in 6 hours, assuming that she reads at a constant speed.
4 hours –> 20 pages
6 hours –> 6/4 x 20 = 30 pages
She reads 60 pages in 6 hours.