Between 1 and 31, n numbers have been inserted in such a way that the resulting sequence is an A. P. and the ratio of 7th and (n – 1)th numbers is 5 : 9. Find the value of n.

Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM

Expert Answer:

Let A1, A2, A3, …, An  be n arithmetic means between 1 and 31 and common difference be d.

Total number of terms = n + 2
First term = 1, last term = (n + 2)th term = 31
Thus, the number of inserted numbers is 14.

Answered by  | 4th Jun, 2014, 03:23: PM