Answer
length of the rectangular swimming pool is $ 120 \; feet $
and width of the rectangular swimming pool is $ 40 \; feet $
its dimensions are $ 40\; feet \; by\; 120\; feet $
Work Step by Step
Let $ l $ represents the length.
and $ w $ represents the width.
The rectangular swimming pool is three times as long as it is wide.
In mathematical form.
$ l=3w $ … (1)
the perimeter of the rectangular swimming pool is $ P=2l+2w $.
From the question $ P=320 \; feet $ plug into above equation.
$ 320=2l+2w $
Substitute the value of $ l $ from equation (1).
$ 320 = 2(3w)+2w $
$ 320 = 6w+2w $
$ 320 = 8w $
$ \frac{320}{8} = w $.
$ 40 = w $
Substitute above value into equation (1).
$ l=3(40) $
$ l=120 $.
