There are 10 digits from 0 to 9.
First digit 10 ways
Second digit 10 ways
Third digit 10 ways
Fourth digit 10 ways
[tex]\text{There are 10}\times10\times10\times10\text{ ways for four digits.}[/tex][tex]\text{There are 10}000\text{ ways for four digits.}[/tex]Hence the total outcomes =10000
Selecting the correct access code on the first try given favorable outcomes =1.
[tex]\text{The probability of randomly selecting the correct access code on the first try=}\frac{favorable\text{ outcome}}{\text{Total outcomes}}[/tex][tex]\text{=}\frac{1}{10000}[/tex][tex]=0.0001[/tex]Hence the probability of randomly selecting the correct access code on the first try is 0.0001.
The probability of not selecting the correct access code on the first try=1-The probability of selecting the correct access code on the first try
The probability of not selecting the correct access code on the first try=1-0.0001
Hence the probability of not selecting the correct access code on the first try=0.9999.