Difference between revisions of "1999 CEMC Gauss (Grade 8) Problems/Problem 3"

(Created page with "== Problem== Which one of the following gives an odd integer? <math>\text{(A)}\ 6^2 \qquad \text{(B)}\ 23-17 \qquad \text{(C)}\ 9\times 24 \qquad \text{(D)}\ 96\div 8 \qquad...")
 
 
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The only odd number from the list is <math>\boxed {\textbf{(E) } 9 \times 41}</math>.
 
The only odd number from the list is <math>\boxed {\textbf{(E) } 9 \times 41}</math>.
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~anabel.disher
 
==Solution 2==
 
==Solution 2==
 
Without evaluating the answers, we can see that <math>6^2</math> is the square of an even number, <math>9 \times 24</math> involves multiplication with an even number, and <math>23 - 17</math> involves two odd numbers, so those are even. This means that we can eliminate those answers.
 
Without evaluating the answers, we can see that <math>6^2</math> is the square of an even number, <math>9 \times 24</math> involves multiplication with an even number, and <math>23 - 17</math> involves two odd numbers, so those are even. This means that we can eliminate those answers.
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Thus, the answer is <math>\boxed {\textbf{(E) } 9 \times 41}</math>.
 
Thus, the answer is <math>\boxed {\textbf{(E) } 9 \times 41}</math>.
 +
 +
~anabel.disher

Latest revision as of 14:34, 15 September 2025

Problem

Which one of the following gives an odd integer?

$\text{(A)}\ 6^2 \qquad \text{(B)}\ 23-17 \qquad \text{(C)}\ 9\times 24 \qquad \text{(D)}\ 96\div 8 \qquad \text{(E)}\ 9\times 41$

Solution 1

Evaluating all of the answer choices, we get:

$6^2 = 36$

$23 - 17 = 6$

$9 \times 24 = 216$

$96 \div 8 = 12$

$9 \times 41 = 369$

The only odd number from the list is $\boxed {\textbf{(E) } 9 \times 41}$.

~anabel.disher

Solution 2

Without evaluating the answers, we can see that $6^2$ is the square of an even number, $9 \times 24$ involves multiplication with an even number, and $23 - 17$ involves two odd numbers, so those are even. This means that we can eliminate those answers.

$9 \times 41$ involves the multiplication of two odd numbers, meaning that it must be the odd number.

Thus, the answer is $\boxed {\textbf{(E) } 9 \times 41}$.

~anabel.disher