Matematické Fórum

stuart clark · 02. 09. 2012 07:08

The Digit $1,2,3,4,5,6,7,8,9$ are written in Random order to form a nine Digit number. Then prove that

the Probability of this number is Divisible by $36$ is $\frac{2}{9}$

laszky · 12. 03. 2018 03:35

The number will be divisible by 9, since the sum of all digits is divisible by 9.

There are 16 ways how the number can ended in order to be divisible by 4

12, 16, 24, 28, 32, 36, 48, 52, 56, 64, 68, 72, 76, 84, 92, 96.

Hence the probability is $\frac{16\cdot 7!}{9!}=\frac{16}{72}=\frac{2}{9}$ .

Matematické Fórum

#1 02. 09. 2012 07:08

probability

#2 12. 03. 2018 03:35

Re: probability

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