Answer
The shorter piece is 3 feet; the longer piece is 15 feet.
Work Step by Step
If we write the length of the shorter piece as x, the length of the longer piece is 5 times x, 5x, and the sum of the short and long piece equals 18, so the expression is:
x + 5x + 18
6x = 18
x = 3
The short piece is x = 3 feet long.
The long piece is 5x = 5*3 = 15 feet long.