A octopus has 8 legs. A hippogriff has 6 legs and 2 pairs of wings. A sphinx has 6 legs and one pair of wings. Now we have all 3 kinds and a total of 18 insects in a cage. We have a total of 118 legs and 20 pairs of wings. How many insects do we have of each kind ?

There are 5 octopus, 7 hippogriff & 6 sphinx.

Let 'A' be the number of octopus, 'B' be number of hippogriff and 'C' be number of sphinx.

A+B+C = 18

8A+6B+6C = 118

2B+C = 20

Solving this, A=5, B=7, C=6