Unit 7 · Data and Percentage

Zoo Animals — Snakes, Lizards, Birds

Lesson 4 of 9

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About this lesson

A zoo has snakes (0 legs), horses (4 legs), and eagles (2 legs). Nine animals, 10 legs total — what is the highest possible number of snakes? The trick: maximising one type means minimising the others, and you can only try a handful of combinations.

Chapters

0:00Introduction
0:21Question
0:54Strategy
1:27Step 1: Set up the equations
2:01Step 2: Minimise H + E to maximise S
2:41Step 3: Verify and rule out 7
3:21Correct answer

Question

At a zoo there are snakes, horses and eagles.

Snakes have no legs, horses have 4 legs, and eagles have 2 legs.

There are 9 of these animals altogether with 10 legs in total.

What is the highest number of snakes that can be at the zoo?

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