A can do a work in 15 days and B in 20 days. 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) 8/17  B) 7/15  C) 3/15  D) 8/15  E) 1/4
Person ( A ) ( B ) ( A+B )   Time - ( 15 ) ( 20 ) (-)   Rate - ( 20 ) ( 15 ) ( 35 )   Work -(300) (300) (300)   therefore A+B requires (300/35) days to complete entire work   For 1st 4 days they work  35 * 4= 
<gadget id="calculator"> 35 * 4</gadget>
<output>140</output>
140   Remaining work is 300 - 140= 
<gadget id="calculator">300 - 140</gadget>
<output>160</output>
160   Remaining fraction of work is= 160/300 = 8/15   Answer 8/15
<result>D</result>
A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is