Question

How many different 7-place license plates are possible if the first 2 places are for letters and the other 5 for numbers? repeat the problem under the assumption that no letter or number can be repeated in a single license plate?

Answer 1

Numbers and letters can repeat:

`26^2\cdot10^5=676\cdot100,000=67,600,000`

No number and letter can repeat:

`26\cdot25\cdot10\cdot9\cdot8\cdot7\cdot6=19,656,000`