Question 82932
By data given that :  


Sam needs 4 days to complete a job


Therefore, he completes 1/4 of a job in one day. 


Lisa needs 6 days to complete a job


Therefore, she completes 1/6 of a job in one day. 


Tom needs 2 days to complete a job.


Therefore, he completes 1/2 of a job in one day. 



So, in total they all need: 


{{{ (1/4) + (1/6) + (1/2) }}}  


Taking LCM, we get: 



==> {{{ (3 + 2 + 6)/12}}} 



==> {{{11/12}}} 


SO WHEN WORKED TOGETHER THEY ALL NEED {{{12/11}}} DAYS TO COMPLETE THE ENTIRE JOB.


HENCE, THE SOLUTION.