How many chickens and rabbits with 21 heads and 56 legs in the same cage?

How many chickens and rabbits with 21 heads and 56 legs in the same cage?

There were x chickens and 21-x rabbits
2x+4(21-x)=56
2x+84-4x=56
-2x=56-84
-2x=-28
x=14
Rabbits: 21-14 = 7

Chickens and rabbits are in the same cage, with 23 heads, 56 legs, and chickens______ Only

Suppose all rabbits, then chickens have: (23 × 4-56) △ 4-2, = 36 △ 2, = 18; answer: there are 18 chickens. So the answer is: 18

There are 15 chickens and 56 legs in the same cage?

Suppose 15 heads are chicken, then there are only 30 legs
(56-30) / (4-2) = 13 rabbits
2 chickens
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