There is an urgent need for reference answers to the sixth grade mathematics ABC test paper 13 cattle grazing problem 15 (1999 Wujiang city competition problem) in Orsay Shenzhen charging primary school. We can assume that there is 1800 kg of grass, so if we put cattle and sheep on the grass,

Eat 1800/45=40 (kg) on average every day? If cows and geese gather together, on average,

Eat one day 1800/60=30 (kg)? If you graze sheep and geese, you eat them every day on average.

1800/90 = 20kg

If you put cows and sheep on the grass, if you put cows and geese on the grass, you can find the difference between sheep and geese.

40-30= 10 (kg) If we let the sheep and geese go, we will already know about the sheep.

The difference with goose is 10 Jin, so we can get sheep-10= goose, and sheep-goose = 10.

20- 10= 10 (kg). Now the two quantities are the same, so 10/2=5 (kg).

It is the average kilogram that geese eat every day. Ask the goose to eat for as many days as possible.

1800/5=360 (days)

The goose knows that the sheep is 1800/(20-5).

= 1800/ 15

120 (days)

The sheep knows, and so does the cow? 1800/(40- 15)

= 1800/25

=72 days

Promise. Yes! Trust me, yes!