Question

Concrete can be purchased by the cubic yard. How much will it cost to pour a slab 13 feet by 13 feet by 3 inches for a patio if the concrete costs $42.00 per cubic yard? Answer only if you know the answer

$197.17

$1774.50

$295.75

$65.72

Answer 1

$65.72

Since the cost is per cubic yard convert the dimensions into yards

• 3 feet = 1 yard ⇔ 13 feet =
`(13)/(3)` yards and

• 36 inches = 1 yard ⇒ 3 inches =
`(3)/(36)` =
`(1)/(12)` yard

volume =
`(13)/(3)` ×
`(13)/(3)` ×
`(1)/(12)` =
`(169)/(108)`

cost = $42 ×
`(169)/(108)` = $65.72

Answer 2

`13(feet) * (1 (yard))/(3 (feet)) * 13 (feet) * (1 (yard))/(3 (feet)) * 3(inches) * (1 (foot))/(12 (inches)) * (1 (yard))/(3 (feet)) = (13*13*3)/(3*3*12*3) (yds)^(3)`

= 1.56 cubic yards *
`(42.00 (dollars))/(1 (cubic yard))` = $65.72

Answer: D