2021 Fall AMC 10B Problems/Problem 3
Contents
[hide]Problem
The expression is equal to the fraction in which and are positive integers whose greatest common divisor is . What is
Solution 1
We write the given expression as a single fraction: by cross multiplication. Then by factoring the numerator, we get The question is asking for the numerator, so our answer is giving .
Solution 2
Denote . Hence,
We observe that and .
Hence, .
Therefore, .
Therefore, the answer is .
~Steven Chen (www.professorchenedu.com)
Video Solution by Interstigation
https://youtu.be/p9_RH4s-kBA?t=160
Video Solution
~Education, the Study of Everything
Video Solution by WhyMath
~savannahsolver
Video Solution by TheBeautyofMath
https://youtu.be/lC7naDZ1Eu4?t=378
~IceMatrix
See Also
2021 Fall AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by Problem 2 |
Followed by Problem 4 | |
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 AMC 10 Problems and Solutions |
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