A, B and C can do a piece of work in 30, 60 and 20 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
A)21 days B)18 days C)20 days D)15 days

• ans 18
  LCM 30,60,20 = 120
  Efficiency of a b c = 4, 2, 6
  3 days = 20 work
  hence 18 days =120 work
• 4 years agoHelpfull: Yes(1) No(3)