【Question 4】On a farm, the grass grows evenly every day. The farm can supply 10 sheep for 20 days, or 14 sheep for 12 days. Then, the new grass that grows on the farm every day is enough for 2 sheep to eat $\qquad$ days.
Analysis:
Assume one sheep eats 1 portion of grass per day
Then the new grass grows daily: $(10 \times 20-14 \times 12) \div(20-12)=4$
(portions)
So the new grass that grows daily is enough for 2 sheep to eat $4 \div 2=2$ (days)