Aptitude - Chain Rule - Discussion

Thanks for the explanation @Saranya.

40 cows 40 bags in 40 days. !

So 1 cow 1 bag each. But this is for 40 days since there are 40 cows and 40 bags.

40 cows eat 40 bags in 1 day
Therefore work done by 40 cows = 40/40 = 1
work done by 1 cow = 1/40
Therefore 1 cow can do 1/40 of whole work
Hence 1/40 + 1/40 + 1/40.....40 times = 1 that is the whole work
Therefore 1 cow will take 40 days to eat 1 bag.

40 cows eat 40 bags in 40 days, i.e 40 cows eat 1 bag in 1day.

In that 1 bag, each cow eats 1/40th in 1 day.

So, how many 1/40th make 1 bag.

1/40 * x = 1,

x = 40.

@Navin.

I think this is the most simple and procedural method. Just think and got down on increasing one parameter how it affects the other parameter as simple as that,

But yet another initiative way to this problem:

40 cows eat 40 bags in days = 40.

So,1 cow will eat 40 bags in days = 40 * 40 (how? One cow will obviously take more time to eat as compared to 40 of them!).

1 cow will eat just 1 bag in days= (40 *40) /40 (how? 1 bag will require less time to be finished!).

= 40.

@mini. Yaar you are explaining superly. Thanks a lot.

40 cows/1 cow = 40 days/1 day (direct proportionate).

Let 40 cows/1 cow = c.

40 days/1 day = d.

c/40 bags = d/x bags.

Putting value of c = 40 & d = 40, we get x = 40;

Question will get rather tough when values differ (say 40 cows, 30 bags, 20 days and we have to find 1 cow to eat 1 bag in how many days.

Solution will be:

c = 40, d = 20 putting in direct relation.

= 40/30 = 20/x.

=> x = 15.

Direct hit method will not be applicable in such type of calculation based method.

Can anyone explain the direct and indirect method of 3 ration?

Explain easily method I can't understand this method.

40 cows 40 bags 40 days.

Considering cows and days.
40 cows 40 day.
=> 1 cow 1600 day(indirect proportion).

Above result is for 40 days.

So for 1 day ans = (1600)/40.
= 40 days.