Aptitude - Pipes and Cistern - Discussion

Discussion Forum : Pipes and Cistern - General Questions (Q.No. 1)
1.
Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes, and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P,Q and R respectively. What is the proportion of the solution R in the liquid in the tank after 3 minutes?
5
11
6
11
7
11
8
11
Answer: Option
Explanation:

Part filled by (A + B + C) in 3 minutes = 3 1 + 1 + 1 = 3 x 11 = 11 .
30 20 10 60 20

Part filled by C in 3 minutes = 3 .
10

Required ratio = 3 x 20 = 6 .
10 11 11

Discussion:
75 comments Page 3 of 8.

Anitha said:   7 years ago
C spend max time 10 minutes.
So, 3/10 minutes.
(3/10)*(20/11).
6/11.

Shailesh Vishwakarma said:   7 years ago
A = 30min fill 100%.
B = 20min fill 100%.
C = 10min fill 100%.

if 3 min filling done all together then,
A =3min fill 10%,
B =3min fill 15%,
C =3min fill 30%.

P =10%,
Q = 15%,
R = 30%.

Total = 55% total tank filled.

Proportion of soln R in total liquid,
=R/Total,
=30/55,
=6/11.
(1)

Vignes R said:   7 years ago
If pipe c is empty the tank. Put negative sign Why use + sign?
(1)

Divya.chippada said:   8 years ago
Part filled by A in one min is given by=1/30 min.
Part filled by B in one min is given by=1/20 min.
Part filled by C in one min is given by=1/10 min.

Now, total (A+B+C)filled in 1 min is given as (1/30+1/20+1/10) by taking lcm and we get 11/20
then in the qn they said after 3 min proportion of R ....clearly we are knowing that (A=p),(B=Q),(C=R).

So we should consider the value of c.
To calculate the proportion of R after 3 min,
Now part filled by C in 3 min is 3x(1/10)=3/10,
the proportion of R=total filled /c filled,
= (3/10)x(20/11),
= 6/11.
(3)

Bibhuti Bhusan Swain said:   8 years ago
@Lalli.

When 1/30+1/20+1/10 add up they give 11/60.

MrunalMehta said:   8 years ago
@Mohsin & @Prabhas.


The part filled by C in 3 mins is 3/10 and part filled by all three combined together is 11/20. To find the proportion of solution are we have to divide 3/10 by 11/20, thus multiplied by 20/11*.

If we divide a number say 25 by 5 we have 2 options.

I) 25/5 i.e- 5 or.
II) 25 x INVERSE OF 5 (I. E- 1/5) = 25x 1/5.
Both are one and the same. Hope this clears.

Prabhas said:   8 years ago
3/10*20/11=6/11?

Plz explain.

Mohsin said:   8 years ago
Why made reciprocal of 11/20? please explain it.

Moon said:   8 years ago
Part filled by (A + B + C) in 3 minutes = 3 = 1 + 1 + 1.

3 x 11 = 11.

30 20 10 60 20

Part filled by C in 3 minutes = 3.
10
Required ratio = 3x20= 6.
10 11 11

Jothi said:   8 years ago
1 =? =>7*3/2=21/2hrs.

Please explain in detail.


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