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.
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)
Naresh said:
8 years ago
In AB/A+B format 30 * 20/20 + 30 = 600/50 = 12.
(2)
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)
Mahadev said:
1 decade ago
How 1/12 is coming please explain?
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.
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.
Karthik said:
1 decade ago
How did you get (1/20+1/30)+1/12?
Jigme wangdi said:
1 decade ago
How comes 3+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.
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.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers