Question

Find the sum of the following 6+13+20+.......+91

Answer 1

Answer:

a=6

d=a2-a1

=13-6

=7

an=91

an=a+(n-1)d

91 = 6+(n-1)7

(n-1)7=91-6

so, the question is incorrect

or the question is not fron ap