Question

Find the middle terms of the A.P 7,13,19,..........,241​

Answer 1

Answer:

Given A.P :- 7,13,19,........241

∴a=7 t

n

=241 d=13−7=6

∴t

n

=a+(n−1)d

∴241=7+(n−1)6

∴

6

241−7

=n−1

∴

6

234

=n−1

∴39+1=n;n=40

∴

2

n

=

2

40

=20......(middle term)

∴

2

n

+1=21 .....(middle term)

∴t

20

=7+(20−1)6

∴t

20

=7+19×6

∴t

20

=7+114=121

∴t

21

=121+6=127

∴ Middle terms are

121

and

127

.