Diana's cd collection is made up of classical and pop cds in the ratio 2; 5.she has 8 classical cds. how many pop cds does she own?

Diana owns 20 pop CDs.

Easiest way to work this out is to find out how much 1 part of this ratio is worth. If 8 classical CDs are 2 parts, then 1 part must equal 4 CDs. As it's in the ratio of 2:5, you have to multiply 1 part (4) by 5 to work out how many pop CDs there are (4 × 5 = 20).