Since 2001, the standard serial numbers on a New York state license plate are 3 letters followed by 4 digits. How many different license plates are possible if letters and digits can be repeated?
Choices:
A) 26 × 3 × 10 × 4
B) 26 × 25 × 24 × 10 × 9 × 8 × 7
C) 26³ × 9 × 9 × 9 × 9
D) 26 × 25 × 24 × 10 000
E) 26³ × 10 000
Solution:   3 repeated letters can be chosen as 26 * 26 * 26   4 repeated digits can be chosen as 10 * 10 * 10 * 10   Answer 26³ × 10 000
<result>E</result>
Since 2001, the standard serial numbers on a New York state license plate are 3 letters followed by 4 digits. How many different license plates are possible if letters and digits can be repeated?