A lawn has equally distributed grass. It takes 24 days to 70 cows and 60 days to 30 cows to eat the whole of grass. How many cows will be needed to eat the grass in 96 days. Select the correct option.
A) 20
B) 30
C) 40
D) 50
E) 60
g - grass at the beginning   r - rate at which grass grows, per day   y - rate at which one cow eats grass, per day   n - no of cows to eat the grass in 96 days   g + 24*r = 70 * 24 * y   g + 60*r = 30 * 60 * y   g + 96*r = n * 96 * y   Solving, n = 20.   20NSWER:20
<result>A</result>
A lawn has equally distributed grass. It takes 24 days to 70 cows and 60 days to 30 cows to eat the whole of grass. How many cows will be needed to eat the grass in 96 days.