word problem

Question

a building contractor is to dig a foundation 30 feet long, 21 feet wide, and 6 feet deep. the contractor pays $10 per load for trucks to remove the dirt. each truck holds 7 cubic yards. what is the cost to the contractor to have all the dirt hauled away?

Answer 1

First, let's convert everything to yards. There are 3 feet in a yard, so:

 

30 feet = 30/3 yards = 10 yards

21 feet = 21/3 yards = 7 yards

6 feet = 6/3 yards = 2 yards

 

Next we'll find the volume of the foundation. Volume = length×width×depth, so:

 

V = 10×7×2 = 140 cubic yards

 

Since each truck holds 7 cubic yards of dirt, we need 140/7 = 20 truck-loads to haul all of the dirt.

 

Finally, since each truck-load costs $10, the contractor will pay $10×20 = $200 total.