Question

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

Answer 1

n= 38
Sum = 6973

This is the ans

Answer 2

let a be the first term and d be the common diff.
l =a+(n-1)d
350=17+(n-1)9
350 -17 =9n-9
333+9=9n
342/9=n
n=38 terms
s38=38/2(2*17 +(38-1)9)
      =6973