Question 304533
If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if all 3 did the job together

sam 4 days  so he does 1/4 of the job in 1 day

Lisa 6 days so she can do 1/6 of the job in 1 day

Tom 2 days so he can do 1/2 job in 1 day

All three can do 1/4 + 1/6 + 1/2 job in 1 day
.
3/12+2/12 +6/12 = 11/12 of the job in 1 day

so to do 1 job they take 12/11 days