Let a =cow, b = sheep, c = Fish, d = camel
C+d = 500
So, d = 500 - c
But d - b + c = 455
500 - c - b + c = 455
So , b = 45
a + b = 240
a = 195
a - c = 215
c = 20
d = 500 - c
= 500 - 20
= 480
So the answer is 480
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