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:
70 comments Page 6 of 7.
Math Master said:
2 decades ago
Better you do like this:
3 pumps take 16 hrs total (8 Hrs a day)
If 1 pump will be working then, it will need 16*3=48 hrs
1 pump need 48 Hrs
If I contribute 4 pumps then
48/4=12 hrs.
3 pumps take 16 hrs total (8 Hrs a day)
If 1 pump will be working then, it will need 16*3=48 hrs
1 pump need 48 Hrs
If I contribute 4 pumps then
48/4=12 hrs.
Sivakumar said:
2 decades ago
a:b::c:d=>bc=ad
Shaunak said:
2 decades ago
It's simple direct and inverse ratio theory. You can apply unitary method,but that'll take a hell lot of time.
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.
Guri said:
2 decades ago
I didn't get how you have solved it. Can you explain me this all step by step?
Hanumanth said:
1 decade ago
pumps*days*hours=pumps*days*hours.
4*1*x=3*8*2.
x=12.
That's simple
4*1*x=3*8*2.
x=12.
That's simple
Simple said:
1 decade ago
(Machine (1) x Time) /Work = (Machine (2) x Time) /Work.
This formula works here also
3 * 8(hrs)* 2(day) /1 =4 * x(hrs) * 1(day)/1
==> x= 12
Here work done is 1 since full tank is to be emptied.
This formula works here also
3 * 8(hrs)* 2(day) /1 =4 * x(hrs) * 1(day)/1
==> x= 12
Here work done is 1 since full tank is to be emptied.
Ashish and Amartya said:
1 decade ago
We found a new method.
step 1- calc the total time for 3 pumps ie(2*8)
2- now for 1 pump time=(2*8)*3
3- " " 4 pump time = ((2*8)*3)/4..ans.
step 1- calc the total time for 3 pumps ie(2*8)
2- now for 1 pump time=(2*8)*3
3- " " 4 pump time = ((2*8)*3)/4..ans.
Aara said:
1 decade ago
Why this formula given below does not work with this question but works with other such similar questions?
(Machine (1) x Time) /Work = (Machine (2) x Time) /Work.
(Machine (1) x Time) /Work = (Machine (2) x Time) /Work.
Kartik said:
1 decade ago
Thanks to mathmaster.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers