Question 320652
Janet can shovel snow from her driveway in 65 min. 
Bill can do the job in 35 min. 
bill can do 1/65 of the job in 1 minute 
bill can do 1/35 of the job in 1 minute
together they do 1/65+1/35 of the job in 1 minute
=35+65 / 35*65
=100/2275
..
They take  2275 / 100  minutes to do the job together
= 22.75 minutes