1. Let chicken x be 3X, then 3X*4+X*2=280 X=20 chicken is 20 rabbit is 60.

2. Let the answer be x, 5X-(20-X)*2=79 X= 17.

3. Damage X, (250-X) * 20- 100x = 4400x = 5

4. Let A be X, (112) * x+(118) * (16-x) =1x = 4.

Boss, this topic is not difficult. You should study hard.