Sunday

What is the fewest number of beads I must pick?

A bag contains 500 beads, each of the same size, but in 5 different colors. Suppose there are 100 beads of each color and I am blindfolded. What is the fewest number of beads I must pick to be absolutely sure there are 5 beads of the same color among the beads I have picked blindfolded?

This is an extension of pigeon hole problem .

Metro Eye: Do not get distracted by total number of beads or number of beads of each color.

Number of different colors, k = 5
Required number, p = 5
Fewest number of tries =  k*(p-1)+1 =  5*4+1 = 21

At least 21 beads needs to be picked up to be absolutely sure there are 5 beads of same color.





  

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