Difference between revisions of "1989 AJHSME Problems/Problem 14"

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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?
 
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?
 
<math>\text{(A)}\ 58 \qquad \text{(B)}\ 123 \qquad \text{(C)}\ 149 \qquad \text{(D)}\ 171 \qquad \text{(E)}\ 176</math>
 
  
 
<cmath>\begin{tabular}[t]{cccc}
 
<cmath>\begin{tabular}[t]{cccc}
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- & & \boxed{} & \boxed{} \\ \hline
 
- & & \boxed{} & \boxed{} \\ \hline
 
\end{tabular}</cmath>
 
\end{tabular}</cmath>
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<math>\text{(A)}\ 58 \qquad \text{(B)}\ 123 \qquad \text{(C)}\ 149 \qquad \text{(D)}\ 171 \qquad \text{(E)}\ 176</math>
  
 
==Solution==
 
==Solution==

Latest revision as of 10:49, 30 July 2023

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?

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

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

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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