Question 202890: How many different sequences of 4 digits are possible if the first digit must be 3, 4, or 5 and if the
sequence may not end in 000? Repetition of digits is allowed.
Answer by dyakobovitch(40)   (Show Source):
You can put this solution on YOUR website! How many different sequences of 4 digits are possible if the first digit must be 3, 4, or 5 and if the
sequence may not end in 000? Repetition of digits is allowed.
Your first digit is 3, 4, or 5.
Assume we have four blanks. Our number is _ _ _ _. The first digit has 3 possibilities. We will multiply possibilities to get our total number of permutations. Since numbers can repeat, our possibilities are 3 x 10 x 10 x 10, or 3,000 total permutations. However, since we can't end in 000, we know that 3,000, 4,000, and 5000 are not possible. Therefore, our answer is 3,000 - 3 or 2,997 permutations.
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David
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