If two pipes function simultaneously, the reservoir will be filled in 12 days.One pipe fills the reservoir 10 hours faster than the other. How many hours does it take the second pipe to fill the reservoir.

a)53 hours
b)13 hours
c)30 hours
d)43 hours

• I think statement should be
  If two pipes function simultaneously, the reservoir will be filled in 12 hours ( not days).One pipe fills the reservoir 10 hours faster than the other. How many hours does it take the second pipe to fill the reservoir.
  
  Then one pipe will fill tank in 20 hrs and second in 30 hrs when opened alone.
  
  
  so c)30 hrs
• 13 years agoHelpfull: Yes(2) No(5)
• Choose from options......take option (c) 30 for faster pipe...so slower would be 20...now their LCM is 60...so faster piper does 2 units and slower 3 units...per hour work done 3+2=5 units....divide total units...in this case 60 by 5...you get 12...hence it is correct option.
• 7 years agoHelpfull: Yes(1) No(0)