Welcome to the 2nd tour

Theme : Combinatorics (difficulty level : easy)

Name | Age | Country | Problem | |
---|---|---|---|---|

Problem 1 | N.P | 17 | France | An unknown coded alphabet contains 6 vowels and 8 consonants. To form a word, we have to alternate the vowels and the consonants. How many words of 9 letters can be formed with this alphabet? |

Problem 2 | N.P | 17 | France | How many are there 9-digit numbers which the sum of figures is even ? |

Problem 3 | N.P | 17 | France | A natural number is said "nice" when its written contains only odd digits. How many are there 4-digit "nice" integers ? |

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