A slab is 30 feet by 14 feet by 5 inches thick. About how many cubic yards of concrete are needed before waste?
Correct Answer
C) 6.48 cubic yards.
Five inches is 0.417 feet. The volume is 30 x 14 x 0.417 = 175.14 cubic feet, and 175.14 / 27 = 6.48 cubic yards.
Why This Is the Correct Answer
Five inches is 0.417 feet. The volume is 30 x 14 x 0.417 = 175.14 cubic feet, and 175.14 / 27 = 6.48 cubic yards.
Why the Other Options Are Wrong
Option A: 4.86 cubic yards.
4.86 cubic yards. is below the supported result for concrete quantity calculation; it likely omits allowance, conversion, coverage, or final round-up.
Option B: 5.40 cubic yards.
5.40 cubic yards. is below the supported result for concrete quantity calculation; it likely omits allowance, conversion, coverage, or final round-up.
Option D: 7.78 cubic yards.
7.78 cubic yards. is above the supported result for concrete quantity calculation; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Memory Technique
Measure to inches, adjust for feet, then let Estimating Exterior set the finish line.
Reference Hint
Study anchor (closed-book): memorize Concrete quantity calculation from California Building Code, California Code of Regulations Title 24. / Title 24 California Building Code concrete quantity concepts; know the rule or calculation trigger without relying on exam-room lookup.
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