SOLUTION: Two pipes P and Q fill an empty cistern in 24 minutes & 32 minutes respectively. Both the pipes being opened together. Find when the first pipe must be turned off so that the empt

Algebra ->  Finance -> SOLUTION: Two pipes P and Q fill an empty cistern in 24 minutes & 32 minutes respectively. Both the pipes being opened together. Find when the first pipe must be turned off so that the empt      Log On


   



Question 953413: Two pipes P and Q fill an empty cistern in 24 minutes & 32 minutes respectively. Both the pipes being opened together. Find when the first pipe must be turned off so that the empty cistern may be just filled in 16 minutes.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Two pipes P and Q fill an empty cistern in 24 minutes & 32 minutes respectively.
Both the pipes being opened together.
Find when the first pipe must be turned off so that the empty cistern may be just filled in 16 minutes.
:
let t = on time of the 1st pipe to accomplish this
let the completed job = 1 (a full cistern)
:
each will do a fraction of the filling, the two fractions add up to 1
t%2F24 + 16%2F32 = 1
reduce the 2nd fraction
t%2F24 + 1%2F2 = 1
multiply equation by 24, cancel the denominators
t + 12 = 24
t = 24 - 12
t = 12 min, then turn the 1st pipe off