Question

Betty had $40 in her pocket. She bought 12 identical bags of popcorn. Betty was left with $10 after buying the popcorn. What was the price, in dollars, of each bag of popcorn?

Answer 1

if you have $10 left then that means you only wasted 30, meaning each bag only cost $2.50.
2.50 x 12=30

Answer 2

40 - 12x = 10
-12x = 10 - 40
-12x = - 30
x = -30/-12
x = 2.50...so each bag of popcorn is : $ 2.50