Answer: Aₙ = Aₙ₋₁*3; where A₀ = 2.5
Step-by-step explanation:
Let's try with some known sequences:
Arithmetic.
The difference between consecutive terms is constant:
7.5 - 2.5 = 5
22.5 - 7.5 = 15
We can already see that it is not an arithmetic sequence.
Geometric:
The ratio between consecutive terms is constant.
7.5/2.5 = 3
22.5/7.5 = 3
67.5/22.5 = 3
...
We can already see that this is a geometric sequence.
Then we can write the n-th term as:
Aₙ = Aₙ₋₁*3, where A₀ = 2.5
