A can do a job in 15days and B in 20days. If they work on it together for 5 days, then the fraction of the work that is left is?
Choose the correct option
A) 2/15  B) 8/15  C) 3/11  D) 5/12  E) 6/13
A's 1 day work = 1/15   B's 1day work = 1/20   A+B 1day work = 1/15 + 1/20  +  1= 
<gadget id="calculator"> +  1</gadget>
<output>1</output>
1/15 + 1/20= 7/60   A+B 5days work = 7/60*5 = 7/12   Remaining work = 1 - 7/12 = 5/12   Answer is 5/12
<result>D</result>
A can do a job in 15days and B in 20days. If they work on it together for 5 days, then the fraction of the work that is left is?