Serena paid $20.20 for 36 rulers and folders. She bought 16 more folders than rulers. If each folder cost $0.50 more than each ruler, how much did each folder cost?

Answer 1

rulers --- x
folders --- x+16

x + x+16 = 36
2x = 20
x = 10
y = 26

so she bought 10 rulers and 26 folders

cost of ruler --- y
cost of folder --- y + .5

10y + 26(y+ .5) = 20.20
10y + 26y + 13 = 20.20
36y = 7.2

y = 0.20

A ruler costs $0.20 and a folder costs $ 0.70