Four - character code ....
Probability
Level
3
There is a 4-character code, with 2 of them being letters and the other 2 being numbers. How many maximum attempts would be necessary to find the correct code? Note that the code is case-sensitive.
The answer is 1622400.
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1 solution
All codes must be one of 6 forms: aa00, a0a0, a00a, 0aa0, 0a0a, 00aa
Each pair of letters has 52 x 52 possible combinations.
Each pair of numbers has 10 x 10 possible combinations.
6 x 52 x 52 x 10 x 10 = 1622400