A can do a piece of work in 80 days and B in 100 days. They work together for 20 days and then B goes away.In how many days will A finish the remaining work?
Select:
A) 33 days	B) 44 days	C) 55 days	D) 42 days	E) 32 days
Explanation:   In this type of questions we first get the finishing of work in 1 minute for both pipes then we will add them to get the result, as:   Part finished by A in 1 day= 1/80   Part finished by B in 1 day = 1/100   Part finished by (A+B) in 1 day = 1/80 + 1/100   = 9/400   So (A+B)'s 20 days work =20*9/400=9/20 Remaining work =1-9/20=11/20. Number days to finish the remaining work by A =80*11/20= 
<gadget id="calculator">80*11/20</gadget>
<output>44</output>
44 days.   Option 44 days
<result>B</result>
A can do a piece of work in 80 days and B in 100 days. They work together for 20 days and then B goes away.In how many days will A finish the remaining work?