Question

The 19th term of an ap is equal to 3 times its 6th term if its 90 term is 19 find the AP

Answer 1

a+18d=3(a+5d)
a-3a+18d-15d=0
2a=3d...(1)
given;
a+89d=19...(2)
solve (1)$(2)...get a and d
and put in series
a, a+d,a+2d,...