Question

Which term of the AP : 3, 8, 13, 18,
is 78?​

Answer 1

Answer:

a =3,d=5 and an =78

<br> we know

an =a+( n-1) d

<br> = 78= 3+5 (n-1 )

= n-1 =15

n= 15+1

n=16