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BlackOut07
Nov24-11, 05:43 PM
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

y=4log(x-10)

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.

HallsofIvy
Nov26-11, 06:32 AM
What was your reasoning behind "x- 10"?

There are 10^1= 10 one digit numbers, 0 to 9.

There are 10^2= 100 two digit numbers, 00 to 99.

There are 10^3= 1000 three digit numbers, 000 to 999.