2013 AMC 8 Problems/Problem 13
Contents
Problem
When Clara totaled her scores, she inadvertently reversed the units digit and the tens digit of one score. By which of the following might her incorrect sum have differed from the correct one?
Video Solution
https://www.youtube.com/watch?v=9FkjSCcdTqY
https://youtu.be/KBM2YN4kKGA ~savannahsolver
Solution
Let the two digits be and
.
The correct score was . Clara misinterpreted it as
. The difference between the two is
which factors into
. Therefore, since the difference is a multiple of 9, the only answer choice that is a multiple of 9 is
.
See Also
2013 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 12 |
Followed by Problem 14 | |
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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