Answer:
52(9/7)^t/1.5
Explanation:
The function N(t) a which models the number of branches t years after Aleksandra began studying her trees ;
Initial number of branches = 52
Increment every 1.5 years = 2/7
N(t) = Initial * (1 + r)^t
t expressed per year = t/1.5
Hence,
N(t) = 52(1 + 2/7)^t/1.5
N(t) = 52(9/7)^t/1.5