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1995 AHSME Problems/Problem 13

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Problem

The addition below is incorrect. The display can be made correct by changing one digit , wherever it occurs, to another digit . Find the sum of and .

\begin{tabular}{ccccccc} & 7 & 4 & 2 & 5 & 8 & 6 \\+ & 8 & 2 & 9 & 4 & 3 & 0 \\\hline 1 & 2 & 1 & 2 & 0 & 1 & 6 \end{tabular}

\mathrm{(A) \ 4 } \qquad \mathrm{(B) \ 6 } \qquad \mathrm{(C) \ 8 } \qquad \mathrm{(D) \ 10 } \qquad \mathrm{(E) \ \text{more than 10} }

Solution

If we change 0 only, it would be incorrect. The same for 1, but 2 we could change to 6. If we try all the other digits, we see that it would be impossible to correct the addition. Thus and .

See also

1995 AHSME (Problems)
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 26 27 28 29 30
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