Problem:
How many different four-digit numbers can be formed by rearranging the four digits in
Answer Choices:
A.
B.
C.
D.
E.
Solution:
To form a four-digit number using and , the digit in the thousands place must be or . There are three places available for the remaining nonzero digit, whether it is or . So the final answer is .
Make a list: and . So numbers are possible.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions