Aptitude - Pipes and Cistern - Discussion

Discussion Forum : Pipes and Cistern - General Questions (Q.No. 13)
13.
A tap can fill a tank in 6 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely?
3 hrs 15 min
3 hrs 45 min
4 hrs
4 hrs 15 min
Answer: Option
Explanation:

Time taken by one tap to fill half of the tank = 3 hrs.

Part filled by the four taps in 1 hour = 4 x 1 = 2 .
6 3

Remaining part = 1 - 1 = 1 .
2 2

2 : 1 :: 1 : x
3 2

x = 1 x 1 x 3 = 3 hours i.e., 45 mins.
2 2 4

So, total time taken = 3 hrs. 45 mins.

Discussion:
53 comments Page 3 of 6.

Elakkiya said:   6 years ago
Thanks @vicky.

Sankar said:   6 years ago
One tap can fill the whole cistern in = 6 hr,
And half(1/2)tank can fill in = 3 hr.

Remaining (1/2)tank will filled with the 4 pipes(1+3) = 3hr = 180min,
4 pipes = 180/4 = 45min.

So the final answer is (1half+2nd half) = 3hr + 45min,
3hr and 45min.

M Ganesh said:   5 years ago
Here we are assuming rate =100
As per the statement,
A
R=100 h=? Capacity =300
=300/100=3.

A+B+C+D =300/400=0.75=45min

=> 3hr +45 min = 3hr 45.

Gopi said:   5 years ago
@ Sravanthi :

only one tap fill the half tank. So, the remaining four should fill the remaining half tank.
Hence. 1 - 1/2 = 1/2.
It's should not be 1-2/3.

Soumen said:   7 years ago
a, b, c, d = 6 hrs.
a=6 * 1/2 = 3 hrs.
then 3 hrs.= 180 minutes.
180/4 = 45 minutes.
3 hrs. 45 minutes.

Kajal said:   7 years ago
Simple and nice explanation @Vicky.

Dinusha said:   8 years ago
Thanks @Krishna.

Jay said:   8 years ago
It should be:

2/3 : 1 :: 1/2 : x.

Dee said:   1 decade ago
If 1 tap takes 6 hours --> 2 taps takes 6/2=3 (half time as fill faster).

If 2 taps takes 6/2=3 (half time)---4 taps takes 3/2=1.5 (i.e 1:30 min).

1:30 min= 60 min +30 min= 90 min.

90 min (time taken by 4 tapes to fill full tank).

But left is only half tank.

So 90/2 = 45 min.

Now total time = 3hour+45 min.

Arun said:   1 decade ago
:: is the sign of proportionality


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