Question

Find the
(i) 30th term of the A.P. 10, 7, 4 ......
(ii) 11th term of the A.P. : –3, –1/2, 2,.....

Answer 1

solution (1) :-

T30 = a + 29d

let ,a = 10 ,

then common difference

(d) = 7- 10 = - 3

now T30 = 10 + 29 ( - 3 )

T30 = 10 - 87

T30= - 77

solution (2) :-

T11 = a + 10 d ------------------------(1)

let , a = -3 , then

d = {-1 / 2 - ( - 3) }= 5 / 2

d = 5 / 2

so now, by putting values of "a" and "d" in (1)

we get ,

T11 = -3 + 10( 5 / 2 )

T11 = -3 + 25

T11 = 22

【 hope it helps 】