Question

Determine the sum of all the multiples of 4 between 1 and 999. Could you please tell me how to find n from here:
n =
d = 4?
t1 = 4?

Sn = n/2 [2 (t1) + (n-1) d]

Answer 1

d= 4, t1 = 4 are correct,
can you tell me what the last term would be ??
last number less than 999, that is divisible by 4 ?

Answer 2

996

Answer 3

is that okay?

Answer 4

yes, thats correct :)
so, 4 is the 1st term, 8 is the 2nd term, so in general
'4n' would be the n'th term, right ? (n=1, t1=4, n=2, t2=8 and so on)
got this ?
so, your "n" would be found from
4n = 996, n=... ?

Answer 5

249

Answer 6

why is 4n the nth term?

Answer 7

see,
the terms are
4,8,12,16,20,......996
right ?
so if you observe that those are multiples of 4 !
like 1st term = 4 *1 = 4
2nd term = 4*2 = 8
3rd term = 4*3 = 12
....
nth term = 4*n =4n

Answer 8

Thank you. I get it now.

Answer 9

welcome ^_^