Tap A can fill an empty tank in 6-hours and Tap B can empty the full tank in 8-hours. If the tank is empty when
tap A is opened at 9:00 am and tap B is opened at 11:00 am, then at what time is the tank filled?
a) 6:00pm b) 3:00 am c) 3:00pm d) 6:00am

• Tap A can fill the tank in 6 hr.
  So, Tap A can fill the tank in 1 hr. = 1/6
  
  Tap B can empty the tank in 8 hr.
  So, Tap B can empty the tank in 1 hr. = 1/8
  
  Tap A fill the tank in 2 hr. = 2*1/6=1/3
  so, empty tank = 1-1/3= 2/3
  
  Now, Net part filled up by A and B in 1 hr. =(1/6-1/8) = 1/24
  since 1/24 of tank can be filled in 1 hr.
  so , 2/3 of tank can be filled in 24*2/3 = 16 hr.
  so 11 A.M + 16 hr. = 3 A.M
  ANs (B)
• 13 years agoHelpfull: Yes(15) No(4)
• 1/3 tank is filled by 11 AM.
  
  Balance 2/3 tank is filled when 2 taps are open.
  In that case,
  Time taken to fill full tank = 1/(1/6-1/8) = 24 hrs
  Time taken to fill 2/3 tank = 24*2/3 =16 hrs
  Means at 3:00 AM
• 13 years agoHelpfull: Yes(7) No(2)