Q:

A work is done by three person A, B and C. A alone takes 10 hours to complete the work but B and C working together takes 4 hours, for the completion of the same work. If all of them worked together and completed 14 times of the work, then how many hours have they worked?

• 1
  42 hr
• 2
  28 hr
• 3
  40 hr
• 4
  20 hr
• 5
  45 hr