Solve the problem.
-A contractor finds that it takes Sam Tockett 9 hours to construct a wall of a certain size. It takes Jim Lowell 7 hours to construct the same wall. How long would it take if they worked together?
A) 16 hours
B) $\frac{16}{63}$ of an hour
C) 1 hour
D) $3 \frac{15}{16}$ hours

Question

Quizplus · Accepted Answer

When working together, their combined rate is the sum of their individual rates. Sam's rate is 1/9 of the wall per hour, and Jim's rate is 1/7 of the wall per hour. Together, they complete 1/9 + 1/7 = 16/63 of the wall per hour. Therefore, it takes them 63/16 hours to complete the wall together, which simplifies to $3 \frac{15}{16}$ hours.

Solve the Problem 1663\frac{16}{63}6316​ Of an Hour C) 1 Hour D) 315163 \frac{15}{16}31615​

Solve the Problem $\frac{16}{63}$ Of an Hour
C) 1 Hour
D) $3 \frac{15}{16}$