Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 9)
9.
Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?
Answer: Option
Explanation:
| Part filled by A in 1 min = | 1 | . |
| 20 |
| Part filled by B in 1 min = | 1 | . |
| 30 |
| Part filled by (A + B) in 1 min = |  |
1 | + | 1 |  |
= | 1 | . |
| 20 | 30 | 12 |
Both pipes can fill the tank in 12 minutes.
Discussion:
15 comments Page 1 of 2.
Priya said:
10 years ago
(1/20 + 1/30) = In order to add both of these fractions first make sure whether the denominator of those two fractions are same. Here the denominators are different.
Cross multiply the two fraction:
= (30+20)/(30*20) = 50/600 = 1/12.
Cross multiply the two fraction:
= (30+20)/(30*20) = 50/600 = 1/12.
Animesh Sharma said:
9 years ago
Two pipes A and B can fill a tank in 45 and 30 hours respectively. If both the pipes are used together, then how long will it take to fill the tank?
Solve this problem.
Solve this problem.
(1)
Jamshaid said:
3 years ago
Tank filled in 4 min = 4 * (1/15+1/20) = 28/60,
Remaining = 32/60.
Time for remaining by B = 32/60 / 1/20 = 32*20/60 = 10.2/60.
Remaining = 32/60.
Time for remaining by B = 32/60 / 1/20 = 32*20/60 = 10.2/60.
Surya sjv said:
9 years ago
Average of these (20+30) / 2 = 25.
Why this is wrong aspect please tell me the reason sir.
Why this is wrong aspect please tell me the reason sir.
Kailash Sharma said:
7 years ago
a=20;
b=30;
l.c.m of 20,30=60;
a's=60/20 =>3;
b's=60/30 =>2;
a+b=60/5 =>12.
b=30;
l.c.m of 20,30=60;
a's=60/20 =>3;
b's=60/30 =>2;
a+b=60/5 =>12.
(4)
Prawesh Pradhan said:
9 years ago
By applying formula,
=> x * y/x + y,
=> 20 * 30/20 + 30,
=> 600/50 = 12.
=> x * y/x + y,
=> 20 * 30/20 + 30,
=> 600/50 = 12.
Rajesh said:
9 years ago
@Animesh.
(45 + 30) = 75, (45 * 30) = 1350.
75/1350,
= 1/18.
Answer: 1/18.
(45 + 30) = 75, (45 * 30) = 1350.
75/1350,
= 1/18.
Answer: 1/18.
Sanjana said:
1 decade ago
LCM of 20 and 30 is 60.
Solve,
1/20+1/30.
= 3+2/60.
= 5/60.
= 1/12.
Solve,
1/20+1/30.
= 3+2/60.
= 5/60.
= 1/12.
Ramkumar said:
1 decade ago
1/20 + 1/30 = 2/50 so = 1/25.
Then how it is possible of 1/12.
Then how it is possible of 1/12.
Myousry said:
9 years ago
Why therefore both pipes can fill the tank in 12 mins?
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