A can do a job in 15days and B in 30days. If they work on it together for 4 days, then the fraction of the work that is left is?  Choose the correct choice from the following answers:  A) 2/15  B) 3/5  C) 3/11  D) 1/12  E) 6/13
A's 1 day work = 1/15   3/5's 1day work = 1/30   A+3/5 1day work = 1/15 + 1/30 = 3/30=1/10   A+3/5 4days work = 1/10*4 = 2/5   Remaining work = 1 - 2/5 = 3/5   Answer is 3/5
<result>B</result>
A can do a job in 15days and B in 30days. If they work on it together for 4 days, then the fraction of the work that is left is?