Question

The ratio of the sum of n terms of two aps is (7n+1):(4n+27).Find the ratio of their 9th terms

Answer 1

Step-by-step explanation:

n/2{2a + (n-1)d} / n/2{2A + (n-1)D} = (7n+1)/(4n+27)

{2a + (n-1)d} / {2A + (n-1)D} = (7n+1)/(4n+27)

let n be 17 {to take value of n first multiply the finding term( for this question is 9) by 2 and then subtract 1 }

(2a + 16d) / (2A + 16D) = (7×17+1)/(4×17+27)

take 2 common

(a + 8d) / (A + 8D) = 120/95

(a + 8d) / (A + 8D) = 24/19

hence ratios of their 8 th term is 24:19