16. Between 1 and 31, m numbers have been inserted in such a way that the resulting sequence is an A. P. and the ratio of and numbers is 5 : 9. Find the value of m.
Let A,B,C.........M be m numbers.
Here we have,
Given : the ratio of and numbers is 5 : 9.
Putting value of d from above,
Thus, value of m is 14.