1/9 + 1/18 = 1/6
6/1 = 6 days
A and B complete a work in 9 days. A alone can do it in 18 days. If both together can do the work in how many days?
Options:
a) 6 days
b) 8 days
c) 5 days
d) 7 days
e) 15 days