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.
Anamika said:
1 decade ago
Math Master's solution is really easy to uderstand
Umesh said:
1 decade ago
Total work (Time to empty the tank by one pump) = 3(pumps)* 8(hours)*2(days)
= 42hours
When 4 pumps are using it will take 42/4= 12 hours
= 42hours
When 4 pumps are using it will take 42/4= 12 hours
Akhilesh Sahu said:
1 decade ago
Please solve my problem
If 38 men , working 6 hours a day ,can do a piece of work in 12 days , find the number of days in which 57 men working 8 hours a day, can do twice that piece of work, supposing that two men of the first set do as much work in 1 hour as 3 men of the secand set do in 3/2 hours.
If 38 men , working 6 hours a day ,can do a piece of work in 12 days , find the number of days in which 57 men working 8 hours a day, can do twice that piece of work, supposing that two men of the first set do as much work in 1 hour as 3 men of the secand set do in 3/2 hours.
Bernard said:
1 decade ago
4 x 1 x x = 3 x 2 x 8
x = (3 x 2 x 8) / (4)
x = 12.
x = (3 x 2 x 8) / (4)
x = 12.
Abhishek said:
1 decade ago
@ Math Master I like your Approach :))
Deepika said:
1 decade ago
Thanks for all for there short cuts.
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?
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.
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