Question

is 68 a term of AP 7, 10,13......?

Answer 1

we know that
nth term =a+(n-1)d

68=7+(n-1)3
68-7=(n-1)3
61/3=n-1


68 is not a term of AP

Answer 2

a=7
d=3

an=a+(n-1)d
68=7+(n-1)3
68 =7+3n-3
68=4+3n
3n=68-4
n=64/3
n=21.33

and it not a term of AP

thanks