A can complete a project in 20 days while B can complete same project in 30 days. If A and B start working together and A leaves the work 5 days before completion of project, then in how many days the project will be completed?
Select:  A) 15  B) 19  C) 20  D) 21  E) 22
A's 1day work=1/20;   B's 1day work=1/30;   (A+B) 1day work=(1/20+1/30)=1/12;   It is given that A leaves the work 5 days before completion of the project..   Thus,B alone does the remaining job in 5 days.   So,In 5 days ,B can do 1/6 w ..   Thus,(A+B) have worked (1-1/6)=5/6 w..   (A+B)can do 1/12 work in 1 day...   They did 5/6 w in 10 days.   Total days=(10+5)= 
<gadget id="calculator">(10+5)</gadget>
<output>15</output>
15   15NSWER:15
<result>A</result>
A can complete a project in 20 days while B can complete same project in 30 days. If A and B start working together and A leaves the work 5 days before completion of project, then in how many days the project will be completed?