Class 11MathematicsPermutation and CombinationDefinition of permutation, Number of permutations with or without repetition, Conditional permutations
MediumAn $n$-digit number is a positive number with exactly $n$ digits. Nine hundred distinct $n$-digit numbers are to be formed using only the three digits $2, 5$ and $7$. The smallest value of $n$ for which this is possible is
- A$6$
- B$7$
- C$8$
- D$9$
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Similar Questions
The number of arrangements of the letters of the word $BANANA$ in which two $N$s do not appear adjacently is
MediumIIT 2002
View SolutionIf ${}^n P_4 = 1680$,then $n =$
The number of six-letter words (with or without meaning) formed using all the letters of the word $VOWELS$ such that all the consonants never come together is ... .
If $0 < r < s < n$ and ${}^n P_r = {}^n P_s$,then find the value of $r + s$.
$60$ words can be made using all the letters of the word $BHBJO$,with or without meaning. If these words are written as in a dictionary,then the $50^{\text{th}}$ word is:
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