What formula would I use to figure out the probability of guessing a 4-digit code, such as an iPhone passcode? Also, what is the answer? So I can make sure I did it right. Thanks!
+128731 If we allow "leading" zeros.....note that there are 10 ways to "guess" each digit..(0-9)
So..... (10 ways) X (10 ways) X (10 ways) X (10 ways) = 10,000 ways
And, if we're only allowed one "guess,' than our probability of guessing correctly is just
1 / 10,0000
If we can't have a leading zero, then we just have
(9 ways) X (10 ways) X (10 ways) X (10 ways) = 9000 ways
And, if we're only allowed one "guess,' than our probability of guessing correctly is just
1 / 9,0000
+128731 If we allow "leading" zeros.....note that there are 10 ways to "guess" each digit..(0-9)
So..... (10 ways) X (10 ways) X (10 ways) X (10 ways) = 10,000 ways
And, if we're only allowed one "guess,' than our probability of guessing correctly is just
1 / 10,0000
If we can't have a leading zero, then we just have
(9 ways) X (10 ways) X (10 ways) X (10 ways) = 9000 ways
And, if we're only allowed one "guess,' than our probability of guessing correctly is just
1 / 9,0000
