Question

in ap third term is obtained by adding 12 to first term and the last term of ap is 205 then find the number of terms in ap.

Answer 1

Step-by-step explanation:

given,

a3=12+a

an=a+(n-1)d=205

a+2d=12+a

2d=12

d=6

a+(n-1)6=205

a+6n=211

n=(211-a)/6