Solve the problem.
-Frank can type a report in 6 hours. James takes 7 hours to type it. How long will it take the two of them typing together?
A) $42 \mathrm { hr }$
B) $\frac { 1 } { 13 } \mathrm { hr }$
C) $\frac { 1 } { 42 } \mathrm { hr }$
D) $\frac { 42 } { 13 } \mathrm { hr }$

Question

Quizplus · Accepted Answer

Frank's typing rate is $1/6$ of the report per hour, and James's typing rate is $1/7$ of the report per hour. Together, they type $(1/6 + 1/7) = (7/42 + 6/42) = 13/42$ of the report per hour. Therefore, it will take them $42/13$ hours to complete the report together.

Solve the Problem 42hr42 \mathrm { hr }42hr B) 113hr\frac { 1 } { 13 } \mathrm { hr }131​hr

Solve the Problem $42 \mathrm { hr }$ B) $\frac { 1 } { 13 } \mathrm { hr }$