Problem 5 · 2019 Math Kangaroo
Easy
Counting & Probability
careful-counting
Jörg is sorting his socks. Two socks with the same number make one pair. How many pairs can he find?
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Answer: C — 5
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Hint 1 of 2
A pair needs two socks showing the same number.
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Hint 2 of 2
Tally how many socks show each number, then count how many numbers appear twice.
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Approach: tally each number and count those that appear twice
- List the number on every sock and see which numbers show up two times.
- The numbers 1, 2, 3, 5 and 7 each appear on two socks, while 6 and 8 appear only once.
- That makes 5 matching pairs.
- So the answer is C.
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