Solve.
-A painter can finish painting a house in 5 hours. Her assistant takes 7 hours to finish the same job. How long would it take for them to complete the job if they were working together?
A) $\frac { 12 } { 35 }$ hour hours
B)4 hours
C) $2 \frac { 11 } { 12 }$ hours hour
D)6 hours

Question

Quizplus · Accepted Answer

The painter's work rate is $1/5$ of the house per hour, and the assistant's work rate is $1/7$ of the house per hour. Working together, their combined rate is $(1/5 + 1/7)$ houses per hour, which simplifies to $(12/35)$ houses per hour. To find the time taken to complete one house, take the reciprocal of their combined rate, which gives $(35/12)$ hours, or $2 \frac { 11 } { 12 }$ hours.

Solve -A Painter Can Finish Painting a House in 5 1235\frac { 12 } { 35 }3512​

Solve
-A Painter Can Finish Painting a House in 5 $\frac { 12 } { 35 }$