Question

A license plate is to consist of 2 letters followed by 3 digits. Determine the number of different license plates possible if repetition of letters and numbers is not permitted?

Answer 1

I will assume that two of the same letter (such as BB) and two or three of the same digit (such as 211 or 111) can appear on a single license plate. What I assume is meant is that no two license plates can be the same.

In that case, the answer is (26^2)*1000
= 676,000

If not, then the answer is
26*25 * 10*9*8 = 468,000

Answer 2

find n if p(n,4)=42p(n,2)