Bunuel wrote:

If a rectangular billboard has an area of 104 square feet and a perimeter of 42 feet, what is the length of each of the shorter sides?

A. 4

B. 7

C. 8

D. 13

E. 26

Assume the sides to be x and y.

Perimeter = 2x + 2y = 42

Hence x + y = 21 - (i)

Area = xy = 104 - (ii)

Since these are the sides of a billboard, we are dealing with positive numbers only and the options tell us that they are integers.

104 can be written as a product of two numbers as 104*1 or 52*2 or 26*4 or 13*8

Of these, only 13*8 satisfies the equation (i)

Hence the lengths are 13 and 8

Length of shorter side = 8

Option C