Answer:
a(1) = 10
a(n) = a(n-1)·0.6
Explanation:
The first term of the sequence is the one listed first: 10. That means a(1) = 10.
The next term of the geometric sequence will be the first term multiplied by the common ratio. That ratio can be found as the ratio of the second term to the first:
r = 6/10 = 0.6
So, the recursive formula is ...
a(n) = a(n-1)·r
a(n) = a(n-1)·0.6