Question

10th maths the ratio of 6th And 8th terms that are in A. P. is 7;9.find the ratio of 9th term to 13th term. ​

Answer 1

ratio of 6th and 8th term =a+5d/a+7d= 7/9

7( a+7d)= 9(a+5d)

7a+49d = 9a +45d

49d-45d= 9a-7a

4d = 2a

a= 2d

ratio of 9th and 13th term

= a+8d / a+12d = 2d +8d / 2d+12d = 10d /14d = 10/14 = 5/7

ratio of 9th and 13th term = 5:7