**Solution:**

Given that,

First term, a = 17

Last term, l = 350

Common difference, d = 9

Let there be n terms in the A.P., thus the formula for the last term can be written as;

l = a + ( n − 1) d

350 = 17 + ( n − 1)9

333 = ( n − 1)9

( n − 1) = 37

n = 38

S_{n} = n /2 ( a + l )

S_{38} = 38/2 (17 + 350)

= 19 × 367

= 6973

Thus, this A.P. contains 38 terms and the sum of the terms of this AP is 6973.