A can do a piece of work in 80 days. He works at it for 10 days & then B alone
finishes the remaining work in 42 days. In how much time will A and B, working
together, finish the work? Choose the correct choice from the following choices
A) 122days	B) 41days	C) 80days	D) 42days	E) 30days
Work done by A in 10 days=10/80=1/8   Remaining work=(1-(1/8))=7/8   Now, work will be done by B in 42 days.   Whole work will be done by B in   (42*8/7)= 
<gadget id="calculator">  (42*8/7)</gadget>
<output>48</output>
48 days   Therefore, A's one day's work=1/80   B’s one day's work=1/48   (A+B)'s one day's work=1/80+1/48=8/240=1/30   Hence, both will finish the work in 30 days.   answer 30days 30days
<result>E</result>
A can do a piece of work in 80 days. He works at it for 10 days & then B alone
finishes the remaining work in 42 days. In how much time will A and B, working
together, finish the work?