Math CentralQuandaries & Queries


Question from Sam:

I have a locked iPhone and it has all my of my holiday photos on it. I changed the password and then I think I did a incorrect number pattern but anyway I know it ends with 99 and the first 4 digits are 235 and 6 could you please send all of the combinations for this password (without the 99) Thx and plz get back ASAP I need it for school

Hi Sam,

From your description it seems that the digits 2, 3, 5, and 6 are all used in the first four digits of the pass code If so there are only 24 possible pass codes and you can try them in an orderly fashion.

Suppose the first digit is 2.

If the second digit could be 3 and the possible pass code are

2356 or 2365

If the second digit could be 5 and the possible pass codes are

2536 or 2563

If the second digit could be 6 and the possible pass codes are

2635 or 2653

Use an analogous procedure for the other three choices of the first digit.


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