There are n coins, each showing either heads or tails. We would like all the coins to show the same face. What is the minimum number of coins that must be reserved?

Question

Marquez

Computers & Technology

5 September, 15:04

There are n coins, each showing either heads or tails. We would like all the coins to show the same face. What is the minimum number of coins that must be reserved?

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Answers (1)

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Konnor Harper · Answer 1

Its nCr = n! / (r!. (n-r) ! = n!/!. (n-1) ! = n

Explanation:

Here. the arrangement of outcome does not matters, and hence it is a combination. You should know that when arrangement matters then we have to calculate the permutation and its formula is n! / (n-r) !. However, here it is the combination, and hence its nCr or n!/r!. (n-r) !. And here r is 1 as we can have all heads or all tails. And n is n. Hence,

Its nCr = n! / (r!. (n-r) !

=n!/!. (n-1) !

= n