Aptitude - Chain Rule - Discussion
Discussion Forum : Chain Rule - General Questions (Q.No. 1)
1.
3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day must 4 pumps work to empty the tank in 1 day?
Answer: Option
Explanation:
Let the required number of working hours per day be x.
More pumps, Less working hours per day (Indirect Proportion)
Less days, More working hours per day (Indirect Proportion)
| Pumps | 4 | : | 3 |  |
:: 8 : x |
| Days | 1 | : | 2 |
4 x 1 x x = 3 x 2 x 8
 x = |
(3 x 2 x 8) |
| (4) |
x = 12.
Discussion:
69 comments Page 5 of 7.
Sandeep said:
1 decade ago
GIVEN: 3 pumps' 1 hour's work= 1/16
SOLUTION : 1 pump's 1 hour's work= 1/48
4 pumps' 1 hour's work= (1/48)*4 = 1/12
hence 4 pumps will finish the work in 12 hours
SOLUTION : 1 pump's 1 hour's work= 1/48
4 pumps' 1 hour's work= (1/48)*4 = 1/12
hence 4 pumps will finish the work in 12 hours
Sanjit said:
1 decade ago
As a lay man I liked the DPH formula of meher.
Thanks.
Thanks.
Hari said:
1 decade ago
Yes it's very easy to understand solved by Mathmaster. ThanQ.
I can't understand your question Mr. Akhilesh sahu.
I can't understand your question Mr. Akhilesh sahu.
Ram chowdary m said:
1 decade ago
Math master really thank you sir your said easy and simple method.
Kuntal Paul said:
1 decade ago
Mathmaster method is so simple and effective.
Maths lover said:
1 decade ago
@math master and all.
Your approach is right because fortunately question is asking of 1 day. If not. Then we have to divide the answer by number of days. So people take care of that also.
Your approach is right because fortunately question is asking of 1 day. If not. Then we have to divide the answer by number of days. So people take care of that also.
Yogendra said:
1 decade ago
Thanks imraz your method is very easy to understand.
Sudheer said:
1 decade ago
Imraz said well.
Raja said:
1 decade ago
@maher. I am just asking where is the concept of chain rule (indirect propprtion) approach.
Imraz said:
1 decade ago
3 pumps 8 hours 2 days =work
3*8*2=work----->eqn1
now to complete the same work with 4 pumps in 1 day how many hours are required? lets take the hours required as x. then we can write the same work as
4 pump x hours 1 day =work
4*x*1=work ---->eqn2
equating both equation
3*8*2=4*x*1
x=48/4
x=12 hours
3*8*2=work----->eqn1
now to complete the same work with 4 pumps in 1 day how many hours are required? lets take the hours required as x. then we can write the same work as
4 pump x hours 1 day =work
4*x*1=work ---->eqn2
equating both equation
3*8*2=4*x*1
x=48/4
x=12 hours
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers