Chickens and rabbits in the same cage solution formula: (rabbit's feet × the total number of feet - the total number of feet) ÷ (rabbit's feet - the number of feet of the chicken) = the number of chickens; the total number of feet - the number of chickens = the number of rabbits.

Assuming all chickens, the number of rabbits = (2×total number of chickens and rabbits - the difference between the number of chickens and the number of rabbits' feet) ÷ (4+2); assuming all rabbits, the number of chickens = (4×total number of chickens and rabbits + the difference between the number of chickens and the number of rabbits' feet) ÷ (4+2).

Solution tips

If all 46 are rabbits, a **** should have 4×46=184 feet, which is 184-128=56 feet more than the known 128 feet. If you replace a rabbit with a chicken, you have to reduce the number of feet by 4-2=2(feet).

So 46 rabbits should be replaced into how many chickens in order to make the difference of 56 feet will be no, obviously 56 ÷ 2 = 28, as long as 28 chickens to replace 28 rabbits on the line. So the number of chickens is 28 and the number of rabbits is 46-28=18.