18+22+26+30+...+50=? Find the sum of the given arithmetic series.

Question

anonymous · Answer

hah ill let someone else help you with that;)

swag · Answer

@aminah.loves17 Please do not post answers like that if you will not help them.

jwheele1 · Answer

is this a pattern question?   Or do we know what the dots are supposed to be?

anonymous · Answer

its nothing bad so chill

jwheele1 · Answer

ok well...d = 4

jwheele1 · Answer

a = 18

jwheele1 · Answer

Skip to one minute and 48 seconds in http://www.youtube.com/watch?v=UHkueFmPC6s&feature=player_embedded#!

jwheele1 · Answer

ill do it the long ugly way:
18+22+26+30+34 + 38 + 42+46+50

jwheele1 · Answer

18+22+26+30+34 + 38 + 42+46+50
   40    +   56   +     72     +     88   +  50

jwheele1 · Answer

40    +   56   +     72     +     88   +  50
        96        +                160       +  50

ajprincess · Answer

use the formula
$$a_n=a+(n-1)d$$
to find n.
Here a=18, d=4
50=18+(n-1)4
50=18+4n-4
50=14+4n
50-14=4n
36=4n
36/4=n
9=n
Nw use the formula 
$$s=\frac{n(a+l)}{2}$$
where s-sum, n=9, a=18 and l=50

jwheele1 · Answer

96 + 160  +  50
     256     +    50

jwheele1 · Answer

306

jwheele1 · Answer

@ajprincess what answer do you come up with?

ajprincess · Answer

the same 306. @jwheel1

jwheele1 · Answer

cool

jwheele1 · Answer

n = 9 means that there are 9 total numbers in the sequence fyi

jwheele1 · Answer

so your formula is that the sum of the sequence (s) =/is  the number of items (9) times (the difference pattern (4) + one additional step to the right in the sequence) and all of that is divided by 2 (and im not sure why, lol)

anonymous · Answer

$$Sn = \frac{ n ( a+ l) }{ 2 }$$

$$an = a + (n-1)d$$