Question

Matt plans to put concrete on a rectangular portion on his driveway. The portion is 8 feet long and 4 inches high. The price of concrete is $98 per cubic yard. The total cost of the concrete Matts needs is $58.07. Which of the following is closest to the width of the portion of the driveway on which Matt plants to put concrete?

Answer 1

First the cost of $98 /yd³ by the conversion factor that
1 yd³ = 27 ft³.
 ($98 /yd³) (1 yd³ / 27 ft³) = $ 3 17/27/ft³

Let x be the width, the volume of the rectangular portion of the driveway is,

 V = (8 ft) (1/3 ft) x = 8x/3 ft³

Using the given total cost of the protion,
 C = $58.07 = (8x/3 ft³)($ 3 17/27/ft³) 

x = 5.99957 ft
 the answer is  6 feet. (rounded)