Problem Solving

Question

a water main for a street is being laid using water pipes, they come in ether 18-foot sections or 20-foot sections. the designer has determined that the water main would require 14 fewer sections of 20-foot pipe than if 18-foot sections were used. Find the total length of the water main.

Answer 1

Let the total length of the water main be x feet.

no. of 18 ft - no. of 20 ft = 14

x/18 - x/20 = 14

 

(20x-18x)/20*18 = 14

2x = 20*18*14

x = 10*18*14

x = 2520 ft.