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?
9
10
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12
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 6 of 7.

Deepika said:   1 decade ago
Thanks for all for there short cuts.

Hiscan said:   1 decade ago
@Cauverypithan
Math master is rite....coz 3 pumps will empty in 16hrs....
if they r using one pump,then work load ll increase,then 48hrs is rite....
still not clear...
then c...3 pump ll empty one tank in 16hr...so more the no of pump faster it gets emptied,
lesser the no of pump slower it gets emptied...

Naresh said:   1 decade ago
Thanks mehar.

Cauverypithan said:   1 decade ago
Math master method is wrong if 3 pumps works a day for 16 hour and one pump will 16/3 not 16*3.

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

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.

Bernard said:   1 decade ago
4 x 1 x x = 3 x 2 x 8

x = (3 x 2 x 8) / (4)

x = 12.

Abhishek said:   1 decade ago
@ Math Master I like your Approach :))

Ganesh said:   1 decade ago
Mehar. Your Explanation is very easy.


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