Sergei had $75 when he arrived at the mall. He spent $9 at the food court. Then he bought 3 posters that each cost the same amount. Sergei has $27 left. Write and solve an equation to find the cost of one poster.

Question

A. $9

B. $3

C. $13

D. $7

Answer 1

x = cost of one poster

75 - 9 - 3 x = 27

66 - 3 x = 27

Subtract 27 to both sides

39 - 3 x = 0

Add 3 x to toth sides

39 = 3 x

x = 39 / 3 = 13

Cost of one poster = $13