Ben franklin's gift of $2,000 to New York City grew to 9,000,000 in 200 years. At what interest rate compounded annually would this growth occur?

We need to use the compound interest formula where the future amount is determined by

A = P (1 + r/n) nt

A = future or present amount = 5,000,000

P = initial amount invested = 8,000

r = interest rate as a decimal (to be determined)

n = # times compounded in a year = 1

t = # years = 200

5000000 = 8000 (1+r/1) 1 (200) = 8000 (1+r) 200

(1+r) 200 = 5,000,000/8,000

(1+r) 200 = 625

1+r = 200√625

1 + r = 6251/200

r = 6251/200 - 1 = 0.0327

r ≅ 3.27%

r ≅ 3.27% : d