Core TradesQuestion 12 of 700
A rectangular slab measures 20 feet by 25 feet and is 5 inches thick. Approximately how many cubic yards of concrete does it require?
a.About 6.3 cubic yards
b.About 7.7 cubic yards
c.About 9.3 cubic yards
d.About 11.5 cubic yards
Explanation
Area = 20 x 25 = 500 ft^2; thickness = 5/12 = 0.4167 ft; volume = 208.3 ft^3; divided by 27 = about 7.7 cubic yards. A 4-inch slab would give 6.3 and a 6-inch slab 9.3, so only the 5-inch case yields 7.7.
Law Reference: 2025 CA Building Code (CBC) Chapter 19 (Concrete)Practice all 700 questions free — no signup required.
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