Problem 2 · 2011 Math Kangaroo
Easy
Arithmetic & Operations
careful-counting
Elsa has 3 tetrahedra and 5 dice. How many faces do these eight objects have altogether?
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Answer: A — 42
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Hint 1 of 2
How many faces does one tetrahedron have, and how many does one die have?
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Hint 2 of 2
Multiply each face count by how many of that solid there are, then add.
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Approach: count faces of each solid and total
- A tetrahedron has 4 faces; three of them give 3×4=12.
- A die (cube) has 6 faces; five of them give 5×6=30.
- Altogether 12+30=42 faces.
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