Question

$12 haircut 15 % tip

Answer 1

12
* .15
60
12
180
$1.80

Answer 2

x/12=15/100
x/12=3/20
cross multiply
12*3=x*20
36=20x
divide both sides by twenty.
1.8=x
12+1.8=13.8
$13.80 is the answer.