The perimeter is the total of adding all of the side lengths together.
A rectangle has 2 opposite side lengths that are the same/equal to each other. So the perimeter of a rectangle is:
P = L + L + W + W or P = 2L + 2W
[P = perimeter, L = length, W = width]
L = W + 5 [the length is 5 inches longer than the width]
You can substitute (W + 5) for "L" in the equation.
P = 2L + 2W
P = 2(W + 5) + 2W
Since you know the perimeter, you can also plug it in.
60 = 2(W + 5) + 2W Multiply 2 into (W + 5)
60 = 2W + 10 + 2W
60 = 4W + 10 Subtract 10 on both sides
50 = 4W Divide 4 on both sides
12.5 = W
Your width is 12.5 inches, your answer is B