(Q4).If the sum of the first 14 terms of an AP is 1050 and its first term is 10, find the 20
th
term.
Here, S
n
=
; n =
, a =
S
n
=
n
2
[2a + (n-1)d]
=
2
[
a +
d] =
+
d
=
d
∴ d =
∴ a
20
=
+ (
-1)
=
Clear