Davis, this is the solution to the problem:
Step 1: Let's review the information given to us to answer the problem correctly:
Price of three sheets of sheetrock = $ 2
Step 2: Let's calculate the price for 15 sheets, using the Direct Rule of Three, as follows:
Sheets Price
3 2
15 x
_______________________
3 * x = 15 * 2
3x = 30
Dividing by 3 at both sides:
3x/3 = 30/3
x = 10
15 sheets will cost $ 10