1. The grazing speed of cattle is X, the growth speed of grass is Y, and A is the original total amount of pasture grass.

27x*6=6y+a 18x*9=6y+a

23x*9=9y+a

So 5x * 9 = 3y.

Therefore, y= 15x and a=72x.

Let's take days as the unit.

2 1Tx=Ty+a

T= 12

As mentioned above, grass can't be eaten, so a=0.

Imitate the above questions.

3.4.5 A type of topic, you can practice it.