A can do a work in 9 days and B can do the same work in 18 days. If they work together, in how many days will they complete the work? Options:
A) 8
B) 7
C) 5
D) 6
E) 3
One day's work of A and B   = 1/9 + 1/8   = (2+1)/18 = 1/6 So, the time taken to complete the work is 6 days.   Answer: 5
<result>C</result>
A can do a work in 9 days and B can do the same work in 18 days. If they work together, in how many days will they complete the work?