SOLUTION: An ID at the zoo consists of 2 letters followed by 2 number (0-9). How many unique IDs are possible?

Any one of 26 letters of the English alphabet is in the first position;

any one of 26 letters of the English alphabet is in the second position;

any one of 10 digits is in the third position, and

any one of 10 digits is in the fourth position.


All these choices are independent, giving 26*26*10*10 = 67600  different possible IDs.    ANSWER