Question

A construction crew is digging a trench for installing a sewer pipe. The trench is a rectangular prism that is 3 feet wide and 5 feet high. On the first day of work, the trench was 12 feet long. On the second day of work, the crew extended the length of the trench by 8 feet. What is the total volume of the soil removed from the trench during the two days of work?

Answer 1

Simply calculate the volumes of the trench on each day and subtract. On the first day, it had a volume of 3x5x12=180 cubic feet. On the second day, it was extended by 8 feet, so the length is now 20 feet. 3x5x20=300 cubic feet. Now we subtract: 300-180=120 cubic feet, so 120 cubic feet of soil was removed.