Question

(10) In an A.P. 1* term is 1 and the last term is 20. The sum of all terms is = 399
then n =
(A) 42
(B) 38
(C) 21
(D) 19​

Answer 1

Answer:

mam I help you please say

Answer 2

Answer:

Last term ( l ) = 20. Sum of 'N' terms = 399. So, there are 38 terms in that A.P.