Length of deck is 40 feet
Solution:
Sam wants the deck to have an overall perimeter of 60 feet
Perimeter of rectangular deck = 60 feet
Let "L" be the length of rectangle and "W" be the width of rectangle
Given that plans for a rectangular deck call for the width to be 10 feet less than the length
Width = length - 10
W = L - 10 ------ eqn 1
The perimeter of rectangle is given as:
perimeter of rectangle = 2(length + width)
Substituting the known values we get,
60 = 2(L + L - 10)
60 = 2(2L - 10)
60 = 4L - 20
80 = 4L
L = 20
Thus the length of deck is 20 feet