2007-12-11 06:33:53 · 7 answers · asked by Jonathan S 2 in Science & Mathematics ➔ Mathematics
It is the series of numbers between 2 and 50. The means is (2+ 50) / 2 or 26 since they are evenly distributed.
If the average of 25 numbers is 26 then the sum is equal to 25 times 26 or 650.
2007-12-11 06:42:01 · answer #1 · answered by Menehune 7 · 0⤊ 0⤋
Here's a nice way to do it:
2 + 4 + 6 + ... + 50
= 2(1 + 2 + 3.+ ... +25)
= 2(25)(26)/2 = 650.
The sum of the first n whole numbers is n(n+1)/2.
2007-12-11 14:52:08 · answer #2 · answered by steiner1745 7 · 0⤊ 0⤋
The word "sum" means addition, do you have to add together the first 25 even numbers, which are 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40 ,42, 44, 46, 48, and 50.
Which gets 650.
=]
2007-12-11 14:41:54 · answer #3 · answered by Tori 2 · 0⤊ 0⤋
That's like asking "why is 2+2 4?"
Of course, I CAN give you an answer.
It HAS to be even.
2+4+6+8+10=30
12+14+16+18+20=80
Logic says that any sum of a _2+_4+_6+_8+_0
It has to end with a 0
It is also always adding 50 every time. Not just adding 50...
the growth is always 1 thing, plus 50. equation would be x=(x-1)+50
Do you understand that?
So if you add
30
80
130
180
it will end up as 650...
2007-12-11 14:43:15 · answer #4 · answered by HenryHoudini 2 · 0⤊ 1⤋
Addition.
2007-12-11 14:41:21 · answer #5 · answered by Zac B 1 · 0⤊ 1⤋
because thats how it works.
2007-12-11 14:40:46 · answer #6 · answered by Anonymous · 1⤊ 1⤋
good question?
2007-12-11 14:41:30 · answer #7 · answered by Michael O 2 · 0⤊ 1⤋