Solution to Cows and the Meadow Problem

The number of cows required is 20..
For this we have to consider the fact tat the grass is growing continously.. Let y be the rate of growth of grass.. So in 24 days the grass will grow 24y..
Now let the total amount be 1..
So (1+24y) is the amt of grass in 24 days..
In 1 day,70 cows will eat = (1+24y)/24
and 1 cow will eat = (1+24y)/(24*70)

and similarly we get 1 cow will eat (1+60y)/(60*30)
Equating the 2 equations and solving we get y= 1/480.. This is the rate of growth of grass. Substituting this in 1 of the above equations we get 1/1600

So for 96 days Let there be x cows---> (1+96*(1/480))/(96*x) = 1/1600

solving x we get x= 20 cows..