Answer:
The annual rate of return on this investment is 8.29%
Step-by-step explanation:
The computation of the rate of return on this investment is shown below:
Since the copper penny is in 1795 is 1 cent
And, 
1 cent = .01 dollars 
Now 
Year 1796 2018 
Amount (in dollars) 0.01 $390,000 
We know that 
Future Value = Present Value × ((1 + rate )^time period) 
Here, 
t = 2018 - 1795 = 222
So, 
.01 × ((1+rate)^(222)) = $480,000 
(1+rate)^(222) = $48,000,000 
1 + rate = $48,000,000^(1 ÷ 222) 
1 + rate = $48,000,000^(0.004505) 
1+rate = 1.082929503 
rate = 0.082929503 
Hence, The annual rate of return on this investment is 8.29%