Question

If the ratio of the sum of 1st N terms of two A.P is (7n+1):(4n-127) find the ratio of their nth term

Answer 1

Answer:8:-123

8/-123

Step-by-step explanation:

Answer 2

Answer:24/19

7n+1/4n-127=2a+(n-1)d/2A+(n-1)D

Divide the terms of RHS by 2

a+{(n-1)d/2}/A+{(n-1)D/2}

To get the ratio of the 9th term

substitute n-1/2 for 8 and u'll get n as 17

Now substitute n=17 for 7n+1/4n-127

and u'll get 120/95 i.e. 24/19

Hope it helps