Fiona needs to chose a five-character password with a combination of three letters and the even numbers 0, 2, 4, 6, or 8. if she uses her initials, f, j, and s in order as the first three characters, and she does not use the same digit more than once in her password, how many different possible passwords are there? 10 20 24 40

For the five characters of the five-character password, the first three slots are already taken for the initial F, J, S, the password would become,
                                         FJS_ _
The last two slots could be any of the even digits. In the fourth slot, Fiona can have any of the 5 values. On the fifth slot, she can have only 4 choices as the other digit was already used. Multiplying 5 and 4, the answer would be 20. 

40 & 50 in the right corner are the complementary angles as when placed in a sum (added together) they make 90°