Aptitude - Pipes and Cistern - Discussion

First take a, b, c = 5, 6, 12.
Take a lcm of a, b, c = 60.
And divide by 5/60, 6/60, 12/60.

We get the answer of 12, 10,-5 because c can empty the tank it takes it as a negative term.
12 + 10 - 5 = 17.
Then divide by 60/17.
We get 3.58.

So, the answer is3(9/17).

5'6'-12 LCM is 60.
So 12. 10. -5 then 12 + 10 - 5 = 17.
Then 60/17 = 3 (9/17) answer.

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.

Superb explanation. Thanks @Manasa.

A PIPE - 5HRS.
B PIPE- 6HRS.
C PIPE - 12HRS TO EMPTY IN TANK, SO THAT,

A-5 B-6 C-12 (TOTAL L.C.M 60 UNIT TANK CAPACITY).
A-12UNIT, B-10UNIT ,C-5UNIT.

TOGETHER(A+B)-EMPTY(C) = 12+10-5 = 17.
TOTAL UNIT 60/17 = 3.52

@Kaveri.

Pipe A =1/5 hrs & B=1/6 hrs, & C=/12 hrs.

LCM of 5, 6 , 12 = 60.
Units or liter (whatever) of :
A = 5 (hours)/60(units) = 12 units.
B = 6 (hours)/60(units) = 10 units.
C = 12 (hours)/60(units) = 5 units.

Now, add A + B(inlet pipe) - C (outlet pipe)/ 60.
--> 22 - 5/60.
---> 17/60.

How it is possible? Explain, please.

(1/5 + 1/6 - 1/12) = (6+5/30 - 1/12).
= (11/30 -1/12),
= (132-30/360),
= (102/360)dividing numerator &denominator by 2,
= (51/180)dividing numerator &denominator by 3,
= (17/60).

I can't understand this. Anyone explain me clearly?

How 60/17 can write as 3*9/17?