A can have a piece of work done in 8 days, B can work three times faster than the A, C can work five times faster than A. How many days will they take to do the work together ?

(a) 3 days (b) 8/9 days (c) 4 days (d) can't say

• 8/9 days
  
  One day work of A = 1/8
  one day work of B = 3/8
  one day work of C = 5/8
  one day work of all three = 9/8
  So all three will complete work in 8/9 days.
• 13 years agoHelpfull: Yes(21) No(0)
• A's 1 day work is 1/8
  B's 1 day work is 3/8
  C's 1 day work is 5/8
  (A+B+C)'s 1 day work(1/8+3/8+5/8) is 9/8
  so, they can finish the work in 8/9 days
  hence option b is the answer
• 13 years agoHelpfull: Yes(7) No(0)
• ans=option will be (b)
  reason=(A,B and C)'s one day work=1/8+3/8+5/8=9/8
  so for complete work=8/9 days
• 13 years agoHelpfull: Yes(6) No(0)