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 2 of 7.
Celita Lewis said:
1 decade ago
If 3 pumps work for 8 hours than total hours in 1 day is 3 * 8 = 24 hours.
So in 2 days total hours of work is 48 hours.
So for 4 pumps the work distributed is (48 / 4) = 12 hours.
So in 2 days total hours of work is 48 hours.
So for 4 pumps the work distributed is (48 / 4) = 12 hours.
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.
Shivam Mehta said:
6 years ago
There is a direct formula m1d1t1w2= m2d2t2w1,
where m1,m2 = no of men case 1,2.
w1,w2= work done in case 1,2.
d1,d2= no of days in case 1,2.
t1,t2= no of hours in case 1,2.
where m1,m2 = no of men case 1,2.
w1,w2= work done in case 1,2.
d1,d2= no of days in case 1,2.
t1,t2= no of hours in case 1,2.
(7)
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.
Please solve the problem.
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.
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.
Deepika said:
1 decade ago
Hey I have one simple way that is ma formula is n*D*H/w = N1*D1*H1/W1.
Where n = no.of men.
d = days.
h = hours.
w = work.
So my opinion is 3*8*2 = 4*1*x.
x = 12.
Where n = no.of men.
d = days.
h = hours.
w = work.
So my opinion is 3*8*2 = 4*1*x.
x = 12.
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.
Isiko Abudallah said:
6 years ago
Let x be the number of hours taken by the second pump.
A : B
Pump 3 : 4
Days 2 : 1
Hours 8 : x
Hour taken by B,
3*2*8 = 4*1*x.
48 = 4x.
x = 12.
A : B
Pump 3 : 4
Days 2 : 1
Hours 8 : x
Hour taken by B,
3*2*8 = 4*1*x.
48 = 4x.
x = 12.
(48)
Sandeep said:
1 decade ago
GIVEN: 3 pumps' 1 hour's work= 1/16
SOLUTION : 1 pump's 1 hour's work= 1/48
4 pumps' 1 hour's work= (1/48)*4 = 1/12
hence 4 pumps will finish the work in 12 hours
SOLUTION : 1 pump's 1 hour's work= 1/48
4 pumps' 1 hour's work= (1/48)*4 = 1/12
hence 4 pumps will finish the work in 12 hours
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.
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