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sweetshiva9963
How many strings of three decimal digits (0, 1, 2, …, 9) a) do not contain the same digit three times? b) begin with an odd digit?
Consider that there are 10 x 10 x 10 total strings of 3-digit numbers (if you allow leading 0's) There are only 10 where all digits are the same (all 0's through all 9's) So, you have: 10 x 10 x 10 - 10 strings where you don't have 3 identical digits. As for your second question, there are: 5 x 10 x 10 that start with an odd digit which happens to be the same as the number that start with an even digit.
All good now, @sweetshiva9963 ?
Ok! Glad I was able to help you! @sweetshiva9963
Good luck to you in all of your studies and thx for the recognition! @sweetshiva9963
your welcome. Thanks for the help