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

May 27, 2016

$a = 36$

#### 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.

$20 a = 15 \left(a + 12\right)$

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