Kevin plans to put concrete on a rectangular portion of his driveway. The portion is 10 feet long and 3 inches high. The price of concrete is $98 per cubic yard. The total cost of the concrete Keven needs is $72.59. Which of the following is closest to the width of the portion of the driveway on which Kevin plans to put concrete?

3 feet

6 feet

8 feet

10 feet

The answer is 8 feet

1 ft = 12 in

1 in = 0.083 ft

1 yd = 3 ft

1 yd³ = 27 ft³

We know:

l = 10 ft

h = 3 in = 3 * 0.083 ft = 0.25 ft

w = ?

The volume of a rectangular concrete is:

V = l * w * h

V = 10 ft * w * 0.25 ft

V = 2.5w ft²

The price is $98 per cubic yard:

$98/1yd ³ = $98/27ft³ = $3.63/ft³

The price is $3.63 per cubic feet.

The total cost of the concrete Keven needs is $72.59:

V * $3.63 = $72.59

2.5w * 3.63 = 72.59

9.075w = 72.59

w = 72.59 / 9.075

w = 7.99 ≈ 8 ft