Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in:
Here pipes A and B are used for filling the tanks,
A and B takes 5 and 6 hours respectively to fill the tank .
for 1 hour ,A can fill 1/5th of the tank and B can fill 1/6th of the tank.
now tank C is used foe emptying the tank(water is running off from the tank)..it can empty the tank in 12 hours..means for 1 hour it empties 1/12th of water from the tank
NOTE:
A and B are filling the tank whereas C is used for emptying the tank.
therefore add A and B and subtract it from c
now consider how much water gets filled in the tank in 1 hour,
1/5+1/6-1/12=17/60
for 1 hour----17/60
? hours----1
(note: for 1 hour-- 17 parts got filled up out of 60 parts
for "?"hours-- 60 parts get filled up out of 60 (60/60=1)
Here 1 indicates tank gets filled)
just by cross multiplying it
(1*1)=(?*17/60)
?=(17/60)/(1*1)
60/17 hours it can fill the tank.
Hi guys use this concepts to find the solution in easily
Concept 1:
A fill tank in x hrs and B fill in Y hrs and C in z hrs means together fill=?
A&B=X*y/x+y
let that A&B ans as p
then A,B&C=p*z/p+z
Concept 2:
A fill tank in x hrs and B empty in Y hrs then both together work how much time is to empty=?
=x*y/y-x
The tank will be full in