If in the tank, the diameter of an inlet Pipe is four times that of the outlet pipe.If both the pipes are open simultaneously, the tank is filled completely in 2 hours.How much time it will take to empty the completely filled tank if only outlet pipe open ?

• 30 hrs
  since, diameter of the inlet pipe(D) is 4 times the diameter of outlet pipe(d).
  and the water filling considers area of circle made by pipe .
  so, area of circle made by inlet pipe= pi*D*D/4(since area of circle= pi*R*R and R= D/2)
  area of circle made by outlet pipe = pi*d*d/4
  so if D=4d,then area of circle of inlet pipe= 4*4 area of circle of outlet pipe
  now , to fill the tank= work of input pipe - work of output pipe=1/2 (since it took 2 hours to fill the tank when both pipe where open , so w.d. per hour =1/2)
  but work of inlet pipe=16*work of outlet pipe
  (work of inlet pipe)- (work of outlet pipe)=1/2
  16 work of outlet pipe- work of outlet pipe = 1/2
  15 work of outlet pipe=1/2 => work of outlet pipe= 1/30
  thus, outlet pipe will complete its work in 30 hrs
• 11 years agoHelpfull: Yes(2) No(0)