Question 148739
A plumber can install a dishwasher in 50 minutes.
So plumber=1/50


because he installs 1/50 of a dishwasher in 1 minute


apprentice=x, because we don't know


plumber and apprentice=1/40


because together they install 1/40 of a dishwasher in 1 minute


1/50 + x/1=1/40


Common denominator
4/200 + 200x/200 = 5/200


4+200x=5


200x=1


x=1/200


So the apprentice can install 1/200 of a dishwasher in 1 minute
So in 200 minutes.


3 hours and 20 minutes