Core TradesQuestion 123 of 700
A rectangular slab measures 30 ft by 40 ft and is 4 inches thick. How many cubic yards of concrete are needed (before any waste allowance)?
a.14.8 cubic yards
b.11.9 cubic yards
c.17.8 cubic yards
d.44.4 cubic yards
Explanation
Convert 4 inches to 0.333 ft. Volume = 30 x 40 x 0.333 = 400 cubic feet. Divide by 27 (cubic feet per cubic yard): 400 / 27 = 14.8 cubic yards. 44.4 results from forgetting to convert thickness to feet; the other choices come from arithmetic or rounding errors.
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