Question

Find the value of the middle term of the AP 7,13,19,............,247.

Answer 1

Here given,

a= 7

d= 13-7= 6

an= 247

We know,

an= a+(n-1)d

247= 7+(n-1)•6

247-7= (n-1)•6

240/6= n-1

40=n-1

hence , n=41

middle term is 21th

so, a21= 7+20×6

a21=127..........ans.