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
11
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 2 of 7.

Akojenu Felix said:   8 years ago
Maths Master Really Explained It Well. I Need More Of Your Teaching.
(1)

Suhani said:   8 years ago
8 hours * 12 people * 15 days = work;
Let, x people will complete the work in 16 days so-
9 hours * x people * 16 days = work,
8 * 12 * 15 = 9 * x * 16,
x = 10 people.

Sanskriti said:   8 years ago
Working 8 hours a day, 12 people can do a piece of work in 15 days. How many people will complete the same work in 16 days working 9 hours a day?

Please solve the problem.

Haruthra said:   9 years ago
I got the solution by this method.

3 : 16 = 4 : x.
so,
3/4 = x / 16
4x = 64
x = 12.

Therefore, the answer is 12 hours.

Babar said:   9 years ago
3 pumps working 8 hours.
So total hours = 3 * 8 = 24 * 2 = 48 to fill.
So can empty 48/4 = 12 hours.
Then, the answer = 12.
(2)

Ankit said:   9 years ago
Math master's solution is great.

Manasi said:   9 years ago
Thanks for solving the problem. It helps always.

Smit said:   10 years ago
I can't understand please explain.

Kjkj tikhir said:   10 years ago
3 pumps = 8 hrs/day.

1 pump = 8*3 = 24 hrs/day and 48 hrs in 2 days.

Considering 1 day work of 3 pumps we know that 24/3 = 8.

Now f we consider 1 day work of 4 pumps should not it be 24/4 = 6.

Please anyone, why? are we considering for two days when it is asked for 1 day work?
(1)

Ekta Ravish said:   1 decade ago
Its very much easy to solve question using these pattern.


Post your comments here:

Your comments will be displayed after verification.