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 7 of 7.
Miss Mathphobia said:
1 decade ago
I liked MathMaster's method...quite simple and easy 2 understand...
Uttam said:
1 decade ago
@ Math Master
Your approach is good, but it dint use the case that pumps should empty the tank within 1 day, is it doesn't make any difference?
Your approach is good, but it dint use the case that pumps should empty the tank within 1 day, is it doesn't make any difference?
Vishal said:
1 decade ago
3 pumb work in 2 days = 16 hours for empty the tank
1 pump work in 2 days = 16*3 = 48 hours for empty the tank
so 4 pump ...........= (16*3)/4 = 12..
1 pump work in 2 days = 16*3 = 48 hours for empty the tank
so 4 pump ...........= (16*3)/4 = 12..
(1)
Mehar said:
1 decade ago
D P H
2 3 8 ==> Fill the tank
1 4 x ==> Have to do empty same tank ,
so work is same then
2*3*8=1*4*x => x=12.
2 3 8 ==> Fill the tank
1 4 x ==> Have to do empty same tank ,
so work is same then
2*3*8=1*4*x => x=12.
Anil said:
1 decade ago
That's the better way of explaining.
Math Master said:
1 decade 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:
1 decade ago
a:b::c:d=>bc=ad
Shaunak said:
1 decade ago
It's simple direct and inverse ratio theory. You can apply unitary method,but that'll take a hell lot of time.
Guri said:
1 decade ago
I didn't get how you have solved it. Can you explain me this all step by step?
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