Question

The first and the last terms of an AP are 17 and 350.If the common difference
is 9, how many terms are there and what is their sum? ​

Answer 1

Answer:

Given :

a = 17

d = 9

an / l = 350

To Find :

No. of terms, n

Solution :

an = a + ( n - 1 ) d

350 = 17 + ( n - 1 ) × 9

350 = 17 + 9n - 9

350 = 9 + 9n

9n = 350 - 9

9n = 342

$n = \frac{342}{9}$

n = 38

No. of terms are 38.