Q:

 Pipe A alone & pipe B alone can fill the same tank in 5 hours and 4 hours respectively. If the ratio of efficiency of pipe A & B together to that of pipe C alone is 9:2, then find time taken by pipe C alone to fill the same tank?

• 1
  8 hours
• 2
  5 hours
• 3
  6 hours
• 4
  10 hours