Civil Engineering Mechanical Engineering Chemical Engineering Networking Database Questions Computer Science Basic Electronics Digital Electronics Electronic Devices Circuit Simulation Electrical Enigneering Engineering Mechanics Technical Drawing

# Aptitude - Pipes and Cistern - Discussion

@ : Home > Aptitude > Pipes and Cistern > General Questions - Discussion

"In the middle of difficulty lies opportunity."
- Albert Einstein
6.

Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:

 [A]. 60 gallons [B]. 100 gallons [C]. 120 gallons [D]. 180 gallons

Explanation:

 Work done by the waste pipe in 1 minute = 1 - 1 + 1 15 20 24

 = 1 - 11 15 120

 = - 1 .    [-ve sign means emptying] 40

 Volume of 1 part = 3 gallons. 40

Volume of whole = (3 x 40) gallons = 120 gallons.

 Shankarbalaji said: (Sun, Dec 26, 2010 11:29:29 AM) 2 pipes can fill a tank in X and Y times respectively. How to calculate the time taken to fill the tank if both the pipes a open together?

 Zonked said: (Tue, Jan 4, 2011 10:18:14 AM) i dont get this one.

 Karan Ratnaparkhi said: (Fri, Jan 7, 2011 01:38:58 PM) As per the given condition we have 1/20 + 1/24 + 1/3 = 1/15. Here 1/3 refers to waste pipe nd 1/20, 1/24 refer to other 2 pipes.

 Sravanreddypailla said: (Thu, May 5, 2011 04:44:30 AM) Two pipes can fill a tank in 20 and 24 minutes respectively and part filled by them is(1/20+1/24) 1gallon=~4litres All the three pipes working together total tank fills in 15min so 1part fills in 15min waste pipe can empty 3 gallons per minute so the volume of tank emptying by waste pipe is total filled tank minus part filled by to pipes i.e 1/15-(1/20+1/24) x 1min= -1/40 that means in 1min waste pipe is emptying 1/40part of total tank given , waste pipe can empty 3 gallons per minute therefore total volume is 1/40=3 gallons=>120 gallons hence capacity of tank is 120 gallons

 Manasa said: (Sat, Jun 11, 2011 09:06:59 AM) Thanks a lot. SRAVANREDDYPAILLA.

 Raj said: (Wed, Apr 11, 2012 08:09:20 PM) How did 1/20+1/24=11/120. Please explain it ?

 Rabi said: (Wed, Apr 18, 2012 10:04:20 AM) Let the capacity of tank x gallons. then in 1 minute tank filled (x/20+x/24-3)gallons From the question we can write 15(x/20+x/24-3)=x [it took 15 min to fill x gallons] x/20+x/24-x/15=3 (6x+5x-8x)/120=3 3x/120=3 x=120 gallons

 Poonam said: (Thu, Feb 14, 2013 01:35:34 PM) What is mean by galloons?

 Sowmi said: (Wed, Feb 20, 2013 01:19:53 PM) A measure of capacity for liquids. Say water or milk can be measured on gallons.

 Krish said: (Sat, Apr 27, 2013 10:54:24 AM) Let x = no.of minutes to take empty the gallon by leakage. (1/20+1/24-1/x)=1/15. x will get = 40 min. 40*3 = 120 gallon.