Question

How do you solve for a: in `15/a=20/(a+12)`?

Answer 1

`a = 36`

Explanation:

There is one fraction on each side, therefore the quickest and easiest way is to cross multiply. This has the effect of getting rid of the denominators and the equation is then easy to solve.

`20a = 15(a + 12)`

`20a = 15a + 180`
`5a = 180`
`a = 36`