Question

in an ap given a=5,d=3n=50,find n and s

Answer 1

now here d =3n=50 so n=50/3
thus s=n/2(2a+(n-1)d)
s=25/3(10+[50-3/3]50
=25/3(10+47*50/3)
=25/3((30+2350)/3
=(25*2380)/9
= 59500/9