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In a zoo, there are Rabbits and Pigeons. If the heads are counted, there are 200 and if legs are counted, there are 580. How many pigeons are there?

  • A.110
  • B.105
  • C.115
  • D.120

Answer: A

There are 110 pigeons.

Let there be \(r\) rabbits and \(p\) pigeons. Each has one head; rabbits have 4 legs and pigeons 2:

\[ \begin{aligned} r + p &= 200 \\ 4r + 2p &= 580 \\ 2r &= 580 - 400 = 180 \end{aligned} \]

So \(r = 90\) and \(p = 110\). Check: \(4 \times 90 + 2 \times 110 = 580\). 105, 115 and 120 pigeons give 590, 570 and 560 legs.

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