width of a wall

Question

a wall measures 18 feet by 24 feet. A wall mural with area 247 square feet s to be placed on the wall with an even border on all sides. To the nearest tenth of a foot, how wide is the border?

Answer 1

247 = 13 x 19 (both are prime numbers, so that's the only solution)

 

So, the mural is 13 x 19

 

24 - 19 = 5

 

5/2 = 2.5 feet on each side the long way.

 

18 - 13 = 5

 

5/2 = 2.5 feet above and below the mural.