If 12 men or 20 women can do a piece of work in 54 days, then in how many days can 9 men and 39 women together do the work?	Select:
A) 10 days
B) 30 days
C) 20 days
D) 80 days
E) 40 days

Rationale: c 20 days given that 12 m = 20 w = > 3 m = 5 w 9 men + 39 women = 15 women + 39 women = 54 women 20 women can do the work in 54 days . so , 54 women can do it in ( 20 * 54 ) / 54 = 20 days .
Answer: C