Calculating Perimeter of a Rectangle

Tom is creating a rectangular poster for his school project. The length of the poster is 24 inches, and the width is 18 inches. He wants to calculate the perimeter of the poster.

The formula for finding the perimeter $P$ of a rectangle is given by:

$$P = 2(l + w)$$

where $l$ is the length and $w$ is the width. What is the perimeter of Tom's poster?