Math
posted by Justin .
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?

rulers  x
folders  x+16
x + x+16 = 36
2x = 20
x = 10 , then y = 26
so she bought 10 rulers and 16 folders
now to the cost:
cost of ruler  y
cost of folder  y + .5
10y + 16(y+ .5) = 20,2
10y + 16y + 8 = 20.2
26y = 12.2
y = .4692
A ruler costs $0.47 and a folder costs $ 0.97
check:
10(.47) + 16(.97) = 20.22 
I don't know i came here for the answers!!