A can do a piece of work in 10 days and B can do the same work in 12 days. A and B worked together for 1/2 days. How many more days are required to complete the remaining work if they work together?  Choose the correct answer.
A) 3 (5/18)
B) 3 (5/16)
C) 3 (5/11)
D) 4 (21/22)
E) 3 (5/21)
A can do 1/10 of the work in a day.   B can do 1/12 of the work in a 1 day.   Both of them together can do (1/10 + 1/12) part of work in 1 day = (6 + 5)/60 = 11/60   They take 60/11 days to complete the work together.   Given that they already worked for 1/2 days.   The number of days required to complete remaining work =&gt; 60/11 - 1/2 = 109/22 = 4 (21/22) days.   Answer:4 (21/22)
<result>D</result>
A can do a piece of work in 10 days and B can do the same work in 12 days. A and B worked together for 1/2 days. How many more days are required to complete the remaining work if they work together?