How many cubic yards of concrete is needed for the floor slab less the garage and fireplace areas?

• A. 15.5 cubic yards
• B. 18.11 cubic yards
• C. 20 cubic yards
• D. 22.5 cubic yards

Answer: (B)

To determine the amount of concrete required for the floor slab while excluding the allocated areas for the garage and fireplace, it’s essential to follow a systematic approach involving measurement and calculation.

First, the overall dimensions of the slab need to be calculated, typically expressed in square feet. You would measure the length and width of the entire area, then multiply these figures to get the total square footage. After that, you'll find out the thickness of the slab, often expressed in inches. This measurement should be converted to feet to maintain consistent units for volume calculation.

Next, you would calculate the total volume of concrete in cubic feet by multiplying the total square footage by the thickness (in feet). Since you need the answer in cubic yards, it is crucial to convert cubic feet to cubic yards by dividing the cubic feet figure by 27 (as there are 27 cubic feet in a cubic yard).

Once the total volume is calculated, deduct the areas where concrete is not needed—specifically, the calculated areas for the garage and fireplace. This gives a more accurate estimate of the concrete required for the remaining slab area. Finally, with this refined volume, the result should align closely with the option provided, which in this case is 18.11 cubic yards,