[ Grazing Problems.]

The grass grows uniformly and quickly across the entire meadow. It is known that 70 cows would eat it all in 24 days, and 30 cows would take 60 days.

How many cows would eat it all in 96 days?

#
Let a cow eat 1 portion of grass per day. In $60-24=36$ days, the meadow grew $30 \cdot 60-70 \cdot 24=120$ portions. This means, in addition to the 1800 portions eaten by 30 cows over 60 days, another 120 portions will grow over the additional $96-60=36$ days. In total, 1920 portions. Over 96 days, these will be eaten by $1920: 96=20$ cows.

## Answer

20 cows.