Sarah went to the store and spent $6 on 9 pounds of fruit. the apples cost $0.45 per pound, and the pears cost $1.10 per pound. how many pounds of apples and how many pounds of pears did sarah buy?

A + p = 9a = 9 - p
0.45a + 1.10p = 6

0.45(9 - p) + 1.10p = 6
4.05 - 0.45p + 1.10p = 6
-0.45p + 1.10p = 6 - 4.05
0.65p = 1.95
p = 1.95/0.65
p = 3 <=== there were 3 lbs of pears

a + p = 9
a + 3 = 9
a = 9 - 3
a = 6 <== there were 6 lbs of apples