At a sale, a shop was offering a 20% discount for a pair of shoes. Customers can purchase a second pair of shoes at 50% discount. Scott paid $156 for 2 identical pairs of shoes. How much did each pair of shoes cost before the discount?
Call the original price = P
He pays ( P -.20P) = .80P for the first pair of shoes and .50P for the second pair
So
.80P + .50P = 156
1.3P =156
P = 156 / 1.3 = 120
The first pair cost 120 (.80) = $96
And the second piar cost 120 (.50) = $60
+36 
