CPM Homework Help : CCA Problem 4-14

Solve this problem by writing and solving an equation. Be sure to define your variable.

A rectangle has a perimeter of $30$ inches. Its length is one less than three times its width. What are the length and width of the rectangle?

Step 1:

Set up two equations:
$3W−1=L$
$2W+2L=30$

Step 2:

Substitute $(3W−1)$ for $L$ and solve the equation:
$2W+2(3W−1)=30$

Answer:

Width is $4$ inches and length is $11$ inches.