To determine how many floor boards, each 2-1/4 inches wide, are needed to cover a floor that is 15 feet wide, follow these steps:
1. Convert the width of the floor from feet to inches:
- Since 1 foot equals 12 inches, we multiply 15 feet by 12 inches per foot.
[tex]\[
15 \, \text{feet} \times 12 \, \text{inches/foot} = 180 \, \text{inches}
\][/tex]
2. Determine the width of each floor board in inches:
- Each floor board is 2-1/4 inches wide. This can be written as a decimal:
[tex]\[
2 \frac{1}{4} \, \text{inches} = 2.25 \, \text{inches}
\][/tex]
3. Calculate the number of floor boards needed:
- To find out how many boards are needed to cover the 180 inches wide floor, we divide the total width of the floor by the width of each board.
[tex]\[
\frac{180 \, \text{inches}}{2.25 \, \text{inches/board}} = 80 \, \text{boards}
\][/tex]
Therefore, you need 80 floor boards to cover a floor that is 15 feet wide.
So, the correct answer is:
C. 80
