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/sci/ - Science & Math

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7001268 No.7001268 [Reply] [Original]

Just noticed something funny.

Q: Find the average integer between 17 and 25.

First method: (17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25) / 9 = 21

Second method: (17 + 25) / 2 = 21

How do you algebraically reconcile them? Why do they yield the same answer?

>> No.7001336

use the formula fior the sum of an arithmetic sequence.

m:=sum(a_i)/n=(a_1+a_n)/2*1/n=(a_1+a_n)/2

>> No.7001340

>>7001336
average of first and last: 21
of second and second to last: 21
...

i dont see how this is funny, /sci/ sucks

>> No.7001868
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7001868

>>7001268
>not being taught concepts of mean, median, and mode
>highschoolfag detected

>> No.7001885

I never understood averages

>> No.7001908

>>7001268
(17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25) / 9 = ((17 + 25) + (18 + 24) + (19 + 23) + (20 + 22) + (21)) / 9
= ((17 + 25) + (17 + 25) + (17 + 25) + (17 + 25) + (17 + 25) / 2) / 9
= (9 * (17 + 25) / 2) / 9
= (17 + 25) / 2

>> No.7002388

>>7001908

My fuckin nigga, this is just the kind of answer I was looking for. Interesting