In order to solve this problem, we need to use proportions.
We have:
cost in dollars number of bags of ice
8.16 6
x 7
We are assuming that the cost is proportional to the number of bags of ice. So, to find the value x that represents the cost for 7 bags of ice, we can cross multiply the proportions above:
x * 6 = 8.16 * 7
Now if we divide both sides by 6, we isolate the variable x on the left side of the equation, and find its value:
x * 6 = 8.16 * 7
x * 6/6 = 8.16 * 7/6
x = (8.16/6) * 7
x = 1.36 * 7
x = 9.52
Therefore, it would have cost them $9.52.
