Cleaning sidewalks. Edgar can blow the leaves off the

Question

sidewalks around the capitol building in 2 hours using a
gasoline-powered blower. Ellen can do the same job in
8 hours using a broom. How long would it take them
working together?
If someone can show me how to work this problem I can get the answer. Thanks!

Answer 1

what is 1/(1/2 + 1/8) ?

Answer 2

Thanks