SOLUTION: find the average of all even numbers below 25?

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Question 772474: find the average of all even numbers below 25?
Found 2 solutions by Edwin McCravy, oscargut:
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
The average of any number of equally spaced numbers (an arithmetic
sequence or progression) is found by averaing the smallest and largest
term.  The smallest term is 0 and the largest is 24

Average = %28smallest%2Blargest%29%2F2 = %280%2B24%29%2F2 = 24%2F2 = 12.

If you don't count 0, then 

Average = %28smallest%2Blargest%29%2F2 = %282%2B24%29%2F2 = 26%2F2 = 13.

Edwin

Answer by oscargut(2103) About Me  (Show Source):
You can put this solution on YOUR website!
1+3+5+....23
= 12+(0+2+4+...+22) = 12+2(0+1+2+...+11) = 12+2(11)(12)/2 = 12+11(12) =
12(12) = 144
Answer: 144/12 = 12

I can help you with more questions at: mthman@gmail.com
Thanks