1986 AJHSME Problems/Problem 8
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Problem
In the product shown, is a digit. The value of is
\[\begin{tabular}[t]{r} \text{B}2 \\ \times 7\text{B} \\ \hline 6396 \\ \end{tabular}\] (Error compiling LaTeX. Unknown error_msg)
Solution
Note that in any multiplication problem, the only 2 digits that will influence the last digit of the number will be the last digits of each number being multiplied.
So, has a units digit of , so is either or . If , then the product is , which is clearly too small, so
See Also
1986 AJHSME (Problems • Answer Key • Resources) | ||
Preceded by Problem 7 |
Followed by Problem 9 | |
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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