231k views
4 votes
Sally has a pool that is 8 yds. By 10 yds. That is surrounded by a deck of uniform width. The deck has an area of 40 sq. Yds. Find the width of the deck.

User Speigg
by
6.6k points

1 Answer

2 votes

Answer:

1 yard

Explanation:

If x is the width of the deck, then its area is the sum of the areas along each side and the areas of the squares in the four corners. The area along the sides is the product of x and the perimeter of the pool, which is 2(8+10) = 36 yards.

40 = 36x +4x^2

10 = 9x +x^2 . . . . . . divide by 4

x^2 +9x -10 = 0 . . . . put in standard form

(x -1)(x +10) = 0 . . . . . factor

The positive value of x that makes this true is x=1.

The width of the deck is 1 yard.

User Sir Wobin
by
6.9k points