Question

Melanie can do a job in 4 hours. Kim can do the same job in 6 hours. If they work together, how long will it take to complete the job?

Answer 1

melanie can do a job in 4 hours

so she can do 1/4 of the job in 1 hour

Kim does the same job in 6 hours

So he can do 1/6 job in 1 hour

Together they can do 1/4 + 1/6 of the job in 1 hour

1/4 + 1/6

= 3+2 / 12

= 5/12 job in one hour

so 1 job they will do together in 12/5 hours

= 2.4 hours