So the pool plus the deck is twice the area of the pool ...
(10+2w)(15+2w) = 2(10*15)
A rectangular swimming pool is 10m wide and 15m long. The pool is surrounded by a deck of uniform width, whose area is equal to the area of the pool. How wide is the deck?
3 answers
(10 + 2 w) (15 + 2w) = 2 * 10 * 15
150 + 50 w + 4 w^2 = 300
2 w^2 + 25 w - 75 = 0
(2 w - 5) (w + 15) = 0
2 w - 5 = 0
w + 15 = 0
150 + 50 w + 4 w^2 = 300
2 w^2 + 25 w - 75 = 0
(2 w - 5) (w + 15) = 0
2 w - 5 = 0
w + 15 = 0
1500 sq cm