Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Advanced Functions Logarithms

  1. Nov 24, 2011 #1
    1. The problem statement, all variables and given/known data

    A security PIN code is four digits long. Each digit could have the value 0 to 9. if an office building needs 10 security PINs, express the number of codes in logarithmic form with base 10

    3. The attempt at a solution


    I don't know how to do the question, but my best attempt produced what you see above.

    4 represents the # of digits.
    x-10 because of the range 0-9.
  2. jcsd
  3. Nov 26, 2011 #2


    User Avatar
    Science Advisor

    What was your reasoning behind "x- 10"?

    There are [itex]10^1= 10[/itex] one digit numbers, 0 to 9.

    There are [itex]10^2= 100[/itex] two digit numbers, 00 to 99.

    There are [itex]10^3= 1000[/itex] three digit numbers, 000 to 999.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook