Anne wants to make a platform that is 7 feet wide and 10 feet long. If she uses boards that measure

Anne wants to make a platform that is 7 feet wide and 10 feet long. If she uses boards that measure 6 inches wide by 2 feet long, how many boards will she need to complete the job?

Area of platform which is a rectangle:
A = lw
A = 10 * 7
A = 70

Area of boards which are rectangles:
A = lw
A = 2 * 6
A = 12

We divide our platform area by our board area to get the number of boards needed:
Boards needed = Platform Area / Board Area
Boards needed = 70/12
Boards needed = 5.83333

We round up if we want full boards to be 6