Problem 5 · Hamsters, canaries and fish
Heads, wings and legs: a system that unravels by itself.
Integer answer, at most 4 digitsBerta is an animal lover. At her home there are hamsters, canaries and fish. In total there are 24 heads, 14 wings and 62 legs. How many fish are there?
Copa Cangur · SCM
Easy
Closed answer
Reasoned solution
Key idea: only canaries have wings, and the legs are shared between hamsters (4) and canaries (2).
$$2c = 14 \Rightarrow c = 7; \qquad 4h + 2c = 62 \Rightarrow 4h = 48 \Rightarrow h = 12.$$
$$p = 24 - 7 - 12 = 5\ \text{fish}.$$
Answer: 5