Question

In an A.P. 8th term is 16 and 16th term is 48.

(i) Find the common-difference of the A.P. (1)

(ii) Find the 25th term of the A.P​

Answer 1

Solution :-

Let first term of given AP is a and common difference is d .

So,

→ T(n) = a + (n - 1)d

given that,

→ T(8) = a + 7d = 16 -------- (1)

→ T(16) = a + 15d = 48 ------ (2)

then,

→ (a + 15d) - (a + 7d) = 48 - 16

→ 15d - 7d = 32

→ 8d = 32

→ d = 4 (Ans.)

putting in (1),

→ a + 7 * 4 = 16

→ a = 16 - 28

→ a = (-12)

therefore,

→ T(25) = a + 24d = (-12) + 24 * 4 = (-12) + 96 = 84 (Ans.)

Learn more :-

evaluate the expression given by 83 - 81 + 87 - 85 +__________ + 395 - 393 + 399 - 397

https://brainly.in/question/14081691

If the nth term of an AP is (2n+5),the sum of first10 terms is

https://brainly.in/question/23676839