A can do a piece of work 30 days. B can do work in 55 days. In how many days they will complete the work together?	Choose one:
A) 15 days
B) 16 days
C) 19.4 days
D) 17.2 days
E) 18 days

Rationale: "lcm = 330 , ratio = 30 : 45 = 6 : 11 no of days = 330 / ( 6 + 11 ) = 330 / 17 = 19.4 days answer : c"
Answer: C