National Occupational Competency Testing Institute (NOCTI) Carpentry Practice Exam

How many 4-feet by 8-feet drywall sheets are required to cover the walls and ceiling of a room that is 12 feet wide, 8 feet long, by 8 feet high?

1. 4 sheets

2. 6 sheets

3. 9 sheets

4. 12 sheets

The correct answer is: 6 sheets

To determine how many 4-feet by 8-feet drywall sheets are needed to cover the walls and ceiling of a room that measures 12 feet wide, 8 feet long, and 8 feet high, we first need to calculate the total surface area that needs to be covered. 1. **Calculate the area of the walls:** - The room has two pairs of opposite walls. The dimensions of each pair of walls are as follows: - Two walls that are 12 feet wide and 8 feet high each have an area of \( 12 \times 8 = 96 \text{ square feet}\). - Two walls that are 8 feet long and 8 feet high each have an area of \( 8 \times 8 = 64 \text{ square feet}\). - Total wall area can be calculated by adding the areas of all the walls: - Total area of the two wider walls: \( 2 \times 96 = 192 \text{ square feet}\). - Total area of the two longer walls: \( 2 \times 64 = 128 \text{ square feet}\). - Combined wall area: \( 192 + 128 =