Question

the 8th term of an A.P is 17 and the 19th term is 39. find the 25th term

Answer 1

Hi...☺

Here is your answer...✌

GIVEN THAT,

T8 = 17 and T19 = 39

T8 = 17

a + 7d = 17

a = 17 - 7d -----(1)

and

T19 = 39

a + 18d = 39

17 - 7d + 18d = 39 ___ [ from (1) ]

11d = 39-17 = 22

d = 22/11

d = 2

Putting d = 2 in eq(1)
we get

a = 17 - 7(2) = 17 - 14

a = 3

Now,

T25 = a + 24d

= 3 + 24×2 = 3 + 48

= 51

HENCE,

25th term of Given AP is 51

Answer 2

Here is the attachment of the answer.

Hope it helps ..