Q. If one pipe is added for set X and Y and set Z's capacity is increased by 20% on its original value and all the taps are opened at 2.58pm, then at what time does the tank get filled?(If it is initially empty)

Option
A)3.05 pm
b)3.04 pm
C)3.10 pm
D)3.03 pm

• 10 pipes of x fills 0.7th tank in 7 min
  In 1 min 10 pipes fills 0.7/7=1/10th tank
  In 1 min 1 pipe of x fills = (1/10)*(1/10) = 1/100
  => After adding one more pipe=(1/10)+(1/100) = 11/100th tank filled in 1 min
  
  5 pipes of Y fills 3/8th tank in 3 min
  =>In 1 min 5 pipes fills 1/8th tank
  In 1 min 1 pipe fills = 1/40th tank
  After adding one pipe to Y
  => (1/8)+(1/40) = 6/40 = 3/20th tank filled in 1 min
  
  =>8 pipes of z empties 5/10th tank in 10 min.
  In 1 min 8 pipes empties 5/100th or 1/20 th tank.
  =>After Increasing z by 20% => (1/20) + 20/(20*100) = (1/20)+(1/100)
  => 6/100th tank emptied in 1 min
  
  Tank filled in 1 min => (11/100)+(3/20)-(6/100) = 1/5th tank filled
  =>In 1 min=1/5th tank
  => Time taken to fill full tank = 5 min
  => 2:58 PM + 5 min = 3.03 PM
• 7 years agoHelpfull: Yes(1) No(0)
• D) 3.03 PM
  
  Time taken by 1 pipe of x = (1/10)*(1/10) = 1/100
  => (1/10)+(1/100) = 11/100th tank filled in 1 min
  
  Time taken by 1 pipe of y = 1/40
  => (1/8)+(1/40) = 6/40 = 3/20th tank filled in 1 min
  
  Increasing z by 20% => (1/20) + 40/(20*100) = (1/20)+(1/50)
  => 7/100th tank emptied in 1 min
  
  Tank filled in 1 min => (11/100)+(3/20)-(7/100) = 19/100th tank filled
  
  => Time taken to fill full tank = 100/19 min = 5 min 15 sec
  => 2.58 + 5 min = 3.03 PM
• 11 years agoHelpfull: Yes(0) No(4)