Question 1027348
Bob and Joan working together can weed a garden in 6 hours.
let bob take x hours to complete the job alone
Bob does 1/x of the job in 1 hour

  Working alone, Joan takes 3x as long as Bob. 

Joan does 1/3x of the job in 1 hour

1/x + 1/3x = 1/6

solve

4/3x = 1/6
4=x/2

x= 8

Bob takes 8 hours to do the job alone