Difference between revisions of "2023 WSMO Speed Round Problems/Problem 3"

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==Solution==
 
==Solution==
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There are <math>6\cdot2\cdot6 = 72</math> non-red socks. Thus, a pair of red socks is guaranteed after <math>72+2 = \boxed{74}</math> socks have been drawn.
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~pinkpig

Latest revision as of 11:06, 12 September 2025

Problem

There are 6 pairs of socks for each color of the rainbow (red, orange, yellow, green, blue, indigo, violet) in a sock drawer. How many socks must be drawn from the drawer to guarantee that a pair of red socks have been drawn?

Solution

There are $6\cdot2\cdot6 = 72$ non-red socks. Thus, a pair of red socks is guaranteed after $72+2 = \boxed{74}$ socks have been drawn.

~pinkpig