Answer:
0.08, or 8%
Explanation:
The appropriate formula is i = p*r*t, where p is the principal, r is the interest rate as a decimal fraction, and t is the time in years.
We want to calculate r when i, p and t are known.
i
Solving i = p*r*t for r, we get r = ------------
p*t
The interest rate in this case is
$1600
r = ---------------- = 0.08, or 8%
$5000*4