Given:
The sequence is 25, 20, 15, 10, 5.
To find:
The ninth term of the given sequence.
Solution:
We have,
25, 20, 15, 10, 5
It is an AP because the difference between two consecutive terms are same.
Here,
First term (a) = 25
Common difference (d) = 20-25
= -5
The nth terms of an AP is
Where, a is the first term and d is the common difference.
Putting a=25, n=9 and d=-5 to get the 9th term.
Therefore, the ninth term of the given sequence is -15.