n the early 1970's, Canada Post started using six-character postal codes. Each postal code uses three letters and three digits in an alternating pattern. How many different Canadian postal codes are possible?

Question

terenzreignz · Answer

Are you allowed to repeat characters? (ie, can you, for instance, use the letter X twice in the same postal code?)

terenzreignz · Answer

If you are, then the possibilities are

26 x 10 x 26 x 10 x 26 x 10 = 17576000

If you may only use each character (letter or digit) once, then the possibilities are

26 x 10 x 25 x 9 x 24 x 8 = 11232000