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8 votes
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An e-mail password must contain three characters. The password has to contain one numeral from $0 \text{ to } 9$, one upper case and one lower case character from the English alphabet. How many distinct passwords are possible?

  1. $6,760$
  2. $13,520$
  3. $40,560$
  4. $1,05,456$
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1 Answer

Best answer
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10 votes

Select any digit from $10$ digits, one uppercase alphabet from $26$ alphabets and  one lowercase  alphabets  from $26$ alphabet, each combination can permute $3!$ times for ex: $5Ab, 5bA, A5b, Ab5, bA5, b5A$

So, total possible passwords= $(10C1 * 26C1 * 26C1 ) * 3! $ 

$= 40560$

Hence option c) is correct

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