Difference between revisions of "2024 AMC 10B Problems/Problem 25"
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<cmath>3c+1=7a</cmath> | <cmath>3c+1=7a</cmath> | ||
− | Adding all the equations together, we get <math>b+c+3 = 4a</math>. Adding <math>a-3</math> to both sides, we get <math>a+b+c = | + | Adding all the equations together, we get <math>b+c+3 = 4a</math>. Adding <math>a-3</math> to both sides, we get <math>a+b+c = 5a-3</math>. The question states that <math>a,b,c</math> are all relatively prime positive integers. Therefore, our answer must be congruent to <math>2 \pmod{5}</math>. The only answer choice satisfying this is <math>\boxed{92}</math>. |
~lprado | ~lprado |
Revision as of 00:26, 14 November 2024
Solution 1
The block has side lengths of . The block has side lengths of .
We can create the following system of equations, knowing that the new block has 1 unit taller, deeper, and wider than the original:
Adding all the equations together, we get . Adding to both sides, we get . The question states that are all relatively prime positive integers. Therefore, our answer must be congruent to . The only answer choice satisfying this is . ~lprado