2015 AMC 8 Problems/Problem 10
Contents
Problem
How many integers between and
have four distinct digits?
Solution 1
There are choices for the first number, since it cannot be
, there are only
choices left for the second number since it must differ from the first,
choices for the third number, since it must differ from the first two, and
choices for the fourth number, since it must differ from all three. This means there are
integers between
and
with four distinct digits.
(If your too lazy to do , we can notice
and
The units digit must be 6. Therefore the answer is
Video Solution (HOW TO THINK CRITICALLY!!!)
~Education, the Study of Everything
Video solution
https://youtu.be/Zhsb5lv6jCI?t=272
https://www.youtube.com/watch?v=OESYIYjZFdk ~David
~savannahsolver
See Also
2015 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 9 |
Followed by Problem 11 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AJHSME/AMC 8 Problems and Solutions |
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