The sum of the 8th element and the 12th element of an arithmetic progression is 246. The sum of the 10th and the 14th element is 298. What is the value of the 35th term?
F + 7D + F + 11D==246, F + 9D + F + 13D==298, solve for F, D
F==6 - this is the first term D==13 - this is the common difference.
35th term==6 + [34*13]==6 + 442==448 - the 35th term.