Question

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

I got 6 feet for my answer, but I'm not sure if I did this right...Could someone check this for me?

Answer 1

This the problem with non-SI units, conversion is such a nightmare. Anyhow, given $98 per cu.yd and total cost of $72.59, the volume of concrete is 0.7404 cu.yd. Converting the given dimensions to yards:

3.33 yd x (1/12) yd

Solving for the unknown dimension given volume and 2 other dimensions:

.7407 cu. Yd = (3.333 yd)(1/12 yd)(x)

X = 2.6678 yd or 8 feet 

Answer 2

Since he pays $72.59, he does have: $98yard3 = $72.59x which is the same as which is the same as yard3 $98 = x $72.59. This expression is equivalent to yard3×$72.59$98=x yards which is equal to 0.74 yards. This is equal to 20.25 feet. hence, 20.25 =  y* 10 ft * (3/12) ft; y is then equal to 8.1 feet or C. 8 feet.