Question

Anyone know how to do this?

Answer 1

Answer: $\frac{10}{r+5}$

The perimeter of a rectangle is given by the following formula:

$P_{rectangle}=2w+2L$   (1)

Where $w$ is the width of the rectangle and $L$ its length.

According to the image:

$w=\frac{2}{r+5}$   (2)

$L=\frac{3}{r+5}$   (3)

So, if we want to find an expression for the perimeter, we have to substitute equations (2) and (3) in (1):

$P_{rectangle}=2(\frac{2}{r+5})+2(\frac{3}{r+5})$   (4)

Solving and simplifying:

$P_{rectangle}=\frac{10}{r+5}$ >>>This is the expression

Therefore, the correct answer is option B.