Problem 14 · 2013 Math Kangaroo
Medium
Arithmetic & Operations
careful-counting
In a shop you can buy oranges in bags of 4 or bags of 10. Pedro wants to buy exactly 48 oranges. What is the smallest number of bags he must buy?
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Answer: C — 6
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Hint 1 of 3
Fewer bags means use the big bags of 10 as much as you can.
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Hint 2 of 3
Try four bags of 10, which is 40 oranges, and see how many oranges are still needed.
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Hint 3 of 3
Fill the leftover with bags of 4, then count how many bags you used altogether.
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Approach: use the largest bags first
- Four bags of 10 give 40, leaving 8, which is two bags of 4.
- That is 4 + 2 = 6 bags, and no smaller number of bags reaches exactly 48.
- So he needs 6 bags.
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