Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 12)
12.
A large tanker can be filled by two pipes A and B in 60 minutes and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half?
Answer: Option
Explanation:
| Part filled by (A + B) in 1 minute = |  |
1 | + | 1 |  |
= | 1 | . |
| 60 | 40 | 24 |
Suppose the tank is filled in x minutes.
| Then, | x | |
1 | + | 1 | |
= 1 |
| 2 | 24 | 40 |
 |
x | x | 1 | = 1 |
| 2 | 15 |
x = 30 min.
Discussion:
51 comments Page 3 of 6.
M ramesh said:
1 decade ago
This problem solving easily this type.
Total time is = x.
b time = a+b time.
b one minute capacity = 2.5.
a+b one minute capacity = 2.5+1.66 = 4.16.
b+(a+b) = 1.
2.5*15m = 37.5.
4.16*15m = 62.5.
37.5+62.5 = 100, 15+15 = 30.
Total time is = x.
b time = a+b time.
b one minute capacity = 2.5.
a+b one minute capacity = 2.5+1.66 = 4.16.
b+(a+b) = 1.
2.5*15m = 37.5.
4.16*15m = 62.5.
37.5+62.5 = 100, 15+15 = 30.
Shankar said:
9 years ago
Why can't it be In logical manner?
Half time of B + half of the time of (A + B) ==> 20+ (A+B) filling time.
A + B in 1 min = 1/24.
In x min = x/24 ==> 1/2 of Total Volume V.
So x = 12; Total time = 20 + 12 = 32.
Half time of B + half of the time of (A + B) ==> 20+ (A+B) filling time.
A + B in 1 min = 1/24.
In x min = x/24 ==> 1/2 of Total Volume V.
So x = 12; Total time = 20 + 12 = 32.
Sree said:
1 decade ago
@suresh.
What you explained was very simple & easy to understand. But in the question its mentioned leaking the Time taken by pipe (B) & time taken by both pipes (A+B). So how can we subtract 50-20?
What you explained was very simple & easy to understand. But in the question its mentioned leaking the Time taken by pipe (B) & time taken by both pipes (A+B). So how can we subtract 50-20?
Madhu reddy said:
1 decade ago
So simple.
a =60; b= 40; a+b = 60*40/60+40 = 24 (formula).
Let's take tank capacity 2x min (i.e x+x).
x/40 + x/24 = 1 (full tank).
By solving, we get x = 15 min.
Therefore 2x = 2*15 = 30 min.
a =60; b= 40; a+b = 60*40/60+40 = 24 (formula).
Let's take tank capacity 2x min (i.e x+x).
x/40 + x/24 = 1 (full tank).
By solving, we get x = 15 min.
Therefore 2x = 2*15 = 30 min.
Praneeth Reddy said:
8 years ago
A's 1 minute work = 1/60.
B's 1 minute work = 1/40.
half d work done by B and remaining Half work by A&B.
= 1/2 [1/40] + 1/2 [1/24] {because 1/60+1/40=1/24}.
= 1/30.
Work done in 30 min.
B's 1 minute work = 1/40.
half d work done by B and remaining Half work by A&B.
= 1/2 [1/40] + 1/2 [1/24] {because 1/60+1/40=1/24}.
= 1/30.
Work done in 30 min.
(1)
Ayush said:
8 years ago
Here if you do it by simple LCM method u will get 32 answers but if you take 1 minute alternate for both u will get 30 answers as;
(3+5) = 2 minute cycle.
=120(lcm of 60 nd 40)/8 = 30minutes.
(3+5) = 2 minute cycle.
=120(lcm of 60 nd 40)/8 = 30minutes.
Suji said:
1 decade ago
Nothing to confuse last 2 lines of question is changed into eqn.
Given half time to fill. As we don't know min. We take as x ie. X/2.
A and B together+only B.
Given half time to fill. As we don't know min. We take as x ie. X/2.
A and B together+only B.
Viz said:
1 decade ago
x/2(only B) + x/2(A and B together) = 1.
x/2(1/40) + x/2 (1/60+1/40) = 1.
x/80 + x/2(5/120) = 1.
x/80 + 5x/240 = 1.
(3x+5x)/240 = 1.
8x = 240.
x=30 mins.
x/2(1/40) + x/2 (1/60+1/40) = 1.
x/80 + x/2(5/120) = 1.
x/80 + 5x/240 = 1.
(3x+5x)/240 = 1.
8x = 240.
x=30 mins.
Salini said:
1 decade ago
@Madhu.
Here you are considering that B does half of work but in question they had mention only the half of time B does the work. Please clarify my doubt.
Here you are considering that B does half of work but in question they had mention only the half of time B does the work. Please clarify my doubt.
Suresh said:
1 decade ago
Here in this question they give a = 60, b = 40.
Then half of the b is = 20.
After half of the a and b that means a+b/2 = 60+40/2 = 50.
Then, 50-20 = 30.
Then half of the b is = 20.
After half of the a and b that means a+b/2 = 60+40/2 = 50.
Then, 50-20 = 30.
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