Question

Hi! Can someone please help me?

Julie an experienced bricklayer can build a wall in 55 hours, while her daughter can do the job in 66 hours. How long will it take for them to build the wall together?

Answer 1

30 hrs

Explanation:

In 1 hour, J completes 1/55 of job

In that time, D completes 1/66 of job

J + D together complete 1/55 + 1/66 of the job in 1 hour

1/55 + 1/66 = 1/30

Together, it takes them 30 hours to build the wall.