How many cubic yards?

Question

You want to put a 4 inch thick layer of topsoil for a new 25 ft by 32 ft garden. The dirt store sells by the cubic yards. How many cubic yards will you need to order? The store only sells in increments of 1/4 cubic yards.

______ cubic yards

Answer 1

25x32x(4/12)= 800/3 ft^3

= 800/3(27) yd^3 1 cubic yard = 27 cubic feet, 1 ft^3 = 1/27 yd^3

=800/81 cubic yards

= about 9.88 yd^3

divide by 1/4

= 3200/81

= about 39.506

40 increments are needed