Question

How many inches of pipe will he have left after he makes the repair?

Answer 1

We need to convert the units of measure from feet to inches, and then subtract the amount he used (8ft, 6in) from the amount he had (12 ft).

We know that each foot corresponds to 12 inches:

$\text{ ft}=12\text{ in}$

Thus, we have:

$12\text{ ft }=12\cdot12\text{ in }=144\text{ in}$$8\text{ ft }6\text{ in }=(8\cdot12+6)\text{ in }=102\text{ in}$

Therefore, after the repair, he will have:

$(144-102)\text{ in }=42\text{ in}$

Answer: 42 inches