Asked by Ayomide

If the sum of the first n terms of the series 4 + 7 + 10 + ... is 209, find n.
Answered by Steve
n/2 (2*4 + (n-1)*3) = 209
1/2 (3n^2+5n) = 209
3n^2+5n-418 = 0
(3n+38)(n-11) = 0
n=11
Answered by emmanuel
209
Answered by Gabriel
Very helpful and simplify. Thanks
Answered by Joyful
The answer is 11.
There are no AI answers yet. The ability to request AI answers is coming soon!