Let's do it in a strange way in two steps.

1, ask for mares and ponies *** 100 horse pack 100 basket of fruits, how many mares and ponies are there.

If all mares are mares, they can carry 200 baskets. Every time a mare changes a pony, it will lose 1.5 baskets, so there are ponies (200-100) \1.5 = 200 \ 3, and mare 100-200 \ 3.

2. Ask for *** 100 horses and 100 baskets of fruits, and how many horses and ponies are there.

All the big horses carry 300 baskets. If you change a big horse into a pony, you will lose 2.5 baskets, and the pony will have (300- 100)\2.5=80 horses and 20 horses.

To sum up, 65438 mares +000 \ 3 horses, 20 horses and (200 \ 3+80) ponies = 440 \ 3 horses, so there are 200 horses carrying 200 baskets of fruits, divided by 2,50 mares, 10 horses and 220 ponies.

Then there are two problems, one is that the number of mares is less than 20, and the other is that the number of horses is an integer, so the result needs to be adjusted, because the number of baskets to be lifted is large >: mare > pony, and the number of mares needs to be increased, so the number of horses and ponies will be reduced. Every time a mare is added, two baskets of fruit will be added, and 0.6 horses and 0.4 ponies will be reduced accordingly, and two baskets of fruit will be reduced (sweat, this is still an equation, but there is nothing to do). Therefore, the ratio of mares to ponies is adjusted to 3: 5: 2, and the number of mares and ponies should be rounded to the whole number, so mares increase by 10\3, mares decrease by 2 and ponies decrease by 4\3. The results are as follows: 8 horses carry 24 baskets, 20 mares carry 40 baskets and 72 ponies carry 36 baskets, which is exactly 100 horses 100 baskets.

In fact, it is very simple to use equations.