A can complete a project in 30 days while B can complete same project in 30 days. If A and B start working together and A leaves the work 10 days before completion of project, then in how many days the project will be completed?
Pick one.
A) 18  B) 19  C) 20  D) 21  E) 22
A's 1day work=1/30;   B's 1day work=1/30;   (A+B) 1day work=(1/30+1/30)=1/15;   It is given that A leaves the work 10 days before completion of the project..   Thus,B alone does the remaining job in 10 days.   So,In 10 days ,B can do 1/3 w ..   Thus,(A+B) have worked (1-1/3)=2/3 w..   (A+B)can do 1/15 work in 1 day...   They did 2/3 w in 10 days.   Total days=(10+10)= 
<gadget id="calculator">(10+10)</gadget>
<output>20</output>
20   ANSWER:20
<result>C</result>
A can complete a project in 30 days while B can complete same project in 30 days. If A and B start working together and A leaves the work 10 days before completion of project, then in how many days the project will be completed?