Question 1147618
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The number of numbers in the first 21 sets is<br>
1+2+3+...+20+21 = (21*22)/2 = 231<br>
The numbers in the 22nd set are the 22 odd numbers starting with the 232nd odd number -- i.e., the 232nd through the 253rd odd numbers.<br>
So the sum of the numbers in the 22nd set is<br>
463+465+...+505 = 22*((463+505)/2) = 11*968 = 10648<br>
Another path to the answer, after finding the answer is the sum of the 232nd through the 253rd odd number....<br>
The sum of the first n odd numbers is n^2.  So the sum of the 232nd through 253rd odd number is the sum of the first 253 odd numbers minus the sum of the first 231 odd numbers:<br>
253^2-231^2 = 10648<br>