Problema Solution

karl can clean his room in 3 hours. His brother can do the same job in 4 hours. How long will it take the to finish the job if they work together?

Answer provided by our tutors

Time needed working together: x

So the equation is

1/3 + 1/4 = 1/x

So

x = 12/7

So Time needed working together is 12/7 hours