Question 909815
tutor quick help plz and solution. Ed required 12 hours to lay linoleum tile on his kitchen floor, a job which would take his neighbor Bert only 8 hours to do. They started working together, but after two hours, Bert had to stop and Ed finished the work alone. How many hours more did it take Ed to finish the job?

Ed required 12 hours to lay linoleum tile on his kitchen floor,
he does 1/12 of the job in 1 hour

neighbor Bert only 8 hours to do. 
he does 1/8 of the job in 1 hour

Together they can do (1/8 +1/12) of the job in 1 hour

=5/24 

in 2 hours they do 5*2/24 = 5/12 of the job

Balance job will be 1- 5/12  = 7/12 of the job

Now Ed does 1/12 of the job in 1 hour
he has to do 7/12 of the job 

so he will take (7/12)/(1/12)

= 7 hours