Problema Solution
You are buying decorations for a birthday party. Six rolls of crepe paper and 20 balloons cost $11.90. After you start decorating, you need more supplies. You buy 2 more rolls of crepe paper and 15 more balloons for $6.05. How much did each roll of crepe paper cost?
Answer provided by our tutors
Let:
c = # of crepe papers
b = # of balloons
You know that:
6c + 20b = 11.90
2c + 15b = 6.05
if you multiply the 2nd equation by 3 you get:
6c + 45b = 18.15
then subtract the 1st equation from your new 2nd one
(45 - 20)b = 18.15 - 11.90
25b = 6.25
b = $.25
then just plug your b values into either equation:
6c + 20(.25) = 11.90
6c = 6.90
c = $1.15