Q:

Three pipes A, B and C can fill a cistern in 10 hours, 12 hours and 15 hours respectively. First A was opened. After 2 hour, B was opened and after 4 hours from the start of A, C was also opened. Find the time in which the cistern is just full.

• 1
  2 hours
• 2
  4 hours
• 3
  2 hours 52 min
• 4
  5 hours 44 min.
• 5
  None of these