Difference between revisions of "2022 MMATHS Individual Round Problems/Problem 3"
Arcticturn (talk | contribs) (Created page with "==Problem== Luke and Carissa are finding the sum of the first <math>20</math> positive integers by adding them one at a time. Luke forgets to add one number and gets an answer...") |
Arcticturn (talk | contribs) (→Solution 1) |
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==Solution 1== | ==Solution 1== | ||
| + | The sum of the first <math>20</math> positive integers is <math>\frac {20 \cdot 21}{2} = 210</math>. This means that Luke forgot to add <math>3</math> and Carissa added the number <math>15</math> twice. Therefore, the sum of the number that Luke forgot and the number Carissa added twice is <math>\boxed {18}</math>. | ||
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| + | ~Arcticturn | ||
Latest revision as of 20:18, 18 December 2022
Problem
Luke and Carissa are finding the sum of the first 
positive integers by adding them one at a time. Luke forgets to add one number and gets an answer of 
. Carissa adds a number twice by mistake and gets an answer of 
. What is the sum of the number that Luke forgot and the number that Carissa added twice?
Solution 1
The sum of the first positive integers is 
. This means that Luke forgot to add 
and Carissa added the number 
twice. Therefore, the sum of the number that Luke forgot and the number Carissa added twice is 
.
~Arcticturn
