Puzzle Details

At a recent visit to the reptile house at the local zoo, I counted a total of 27 heads and 70 feet.

I was counting snakes, lizards and people and I know that there were exactly twice as many lizards as people.

How many snakes did I count?

6 snakes: 7 people and 14 lizards.

If we have S snakes, L lizards and P people.

S + L + P = 27          [1]

The 70 feet gives us:

4L + 2P = 70          [2]

We also know that:

L = 2P          [3]

Using [3] in [2] gives:

4 x 2P + 2P = 70

So:

10P = 70

P = 7

Using P = 7 in [2] gives:

4L + 14 = 70

4L = 56

L = 14

Using L = 14 and P = 7 in [1] gives:

S + 14 + 7 = 27

S = 6

So S = 6, P = 7 and L = 14.

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