Question

Matt plans to put concrete on a rectangular portion of 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 Matt needs is $58.07. Which of the following is closest to the width of the portion of the driveway on which Matt plans to put concrete?

Answer 1

onvert 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

So the answer is 6 ft