A man puts a rectangular pool in his yard which is 40 ft by 20 ft.

Question

A man puts a rectangular pool in his yard which is 40 ft by 20 ft. There is a slate tile are 3 1/2 ft wide around the entire perimeter of the pool. The pool and the tile are take up the entire 40 ft by 20 ft. What are the dimensions of the pool?

Answer 1

First, draw a picture !  It doesn't have to be extremely neat, but here is how you use it:

 

The 20-ft side of the yard becomes:

     3 1/2 ft tile   +    side of pool    +    3 1/2 ft tile     =   20 ft

   So,

     width of pool  =  20 - 3 1/2 - 3 1/2

     width of pool =   20 - 7

     width of pool = 13 ft

 

The 40-ft side of the yard becomes:

    3 1/2 ft tile   +   side of pool   +   3 1/2 ft tile   =   40 ft

  So,

    length of pool  =  40 - 3 1/2 - 3 1/2

    length of pool  =  40 - 7

    length of pool  =  33 ft

 

The dimensions of the pool are 13 ft by 33 feet.