Difference between revisions of "2024 AMC 8 Problems/Problem 4"
(→Video Solution 1(easy to digest) by Power Solve) |
|||
Line 8: | Line 8: | ||
-rnatog337 | -rnatog337 | ||
− | ==Video Solution 1(easy to digest) by Power Solve== | + | ==Video Solution 1 (easy to digest) by Power Solve== |
https://youtu.be/HE7JjZQ6xCk?si=sTC7YNSmfEOMe4Sn&t=179 | https://youtu.be/HE7JjZQ6xCk?si=sTC7YNSmfEOMe4Sn&t=179 |
Revision as of 16:56, 25 January 2024
Problem
When Yunji added all the integers from to , she mistakenly left out a number. Her incorrect sum turned out to be a square number. What number did Yunji leave out?
Solution 1
The sum of the numbers from to is Denote the number left out when adding to be . Thus, is a perfect square. We could rigorously solve the values of such that is a perfect square. However, since this is the AMC 8, we can simply try each option. When , we see that , a perfect square. Therefore, our answer is .
-rnatog337