Question

if the fourth term of an A.P is 1 and the sum of its first eight terms is 18 ,find the tenth term of the series

Answer 1

Answer:

-5

Step-by-step explanation:

let firSt term be 'a' and common difference 'd'

a+3d =1 ------(1)

Sum of terms in AP = n/2 [2a+(n-1)d]

=> sum of first 8 terms = 4(2a+7d) = 18----(2)

Solving (1) & (2),

a= 4, d= -1

So, 10th term is a+ 9d = -5