1/20 + 1/30 = 5/60 = 1/12
12 = 12 *2 = 24 days
A can do a job in 20 days and B can do it in 30 days. A and B working together will finish twice the amount of work in days?
A) 22 1/6
B) 24
C) 22 1/0
D) 22 1/9
E) 22 1/1