Art of Problem Solving

1989 AJHSME Problems/Problem 14: Difference between revisions

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New page: ==Problem== When placing each of the digits <math>2,4,5,6,9</math> in exactly one of the boxes of this subtraction problem, what is the smallest difference that is possible? <mat...
 
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{{AJHSME box|year=1989|num-b=13|num-a=15}}
{{AJHSME box|year=1989|num-b=13|num-a=15}}
[[Category:Introductory Algebra Problems]]
[[Category:Introductory Algebra Problems]]
{{MAA Notice}}

Revision as of 23:03, 4 July 2013

Problem

When placing each of the digits $2,4,5,6,9$ in exactly one of the boxes of this subtraction problem, what is the smallest difference that is possible?

$\text{(A)}\ 58 \qquad \text{(B)}\ 123 \qquad \text{(C)}\ 149 \qquad \text{(D)}\ 171 \qquad \text{(E)}\ 176$

\[\begin{tabular}[t]{cccc}  & \boxed{} & \boxed{} & \boxed{} \\ - & & \boxed{} & \boxed{} \\ \hline \end{tabular}\]

Solution

When trying to minimize $a-b$, we minimize $a$ and maximize $b$. Since in this problem, $a$ is three digit and $b$ is two digit, we set $a=245$ and $b=96$. Their difference is $149\rightarrow \boxed{\text{C}}$.

See Also

1989 AJHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 13
Followed by
Problem 15
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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