Question

The ratio of 6th and 8th term of an A.P is 7:9 find the ratio of 9th term to 13th term​

Answer 1

Hi,

5:7

Explanation:

Let's assume a the first term and d the commun difference.

`(a_6)/(a_8) =(7)/(9) \\\\(a+5d)/(a+7d) =(7)/(9) \ cross\ product\ 9a+45d=7a+49d\\\\2a=4d\\\\a=2d\\\\(a_9)/(a_(13)) =(a+8d)/(a+12d)= (2d+8d)/(2d+12d) =(10d)/(14d) =\boxed{(5)/(7) }\\\\`