One pipe fills in 4 hrs and another in 5hrs when they both work alternately
how much time will be taken to fill the tank.

• Work done in one hour by pipe 1 is 1/4
  Work done in one hour by pipe 2 is 1/5
  When they work alternatively work done in 2 hours is 9/20
  For four hour is 18/20 remaining work is 2/20=1/10
  Work will be done by pipe 1=(1/4)x=1/10
  X=2/5 hour =24 minutes
  Total time taken is 4hours and 24 minutes
• 9 years agoHelpfull: Yes(9) No(2)
• 1/4+1/5=9/20 work in 2 days. So one complete work will be in 40/9 days (2*20/9)
• 9 years agoHelpfull: Yes(2) No(0)
• given one pipe capacity to fill the tank P1 = 4hrs=4*60=240 minutes
  another pipe capacity to fill the tank P2 = 5hrs=5*60=300 minutes
  avg of two pipes fill the tank at a time = (P1+P2)/2
  = (240+300)/2
  = (540)/2
  = 270 minutes
  Coverted into hours = 270/60 = 4hrs 30 minutes
• 9 years agoHelpfull: Yes(2) No(1)