Answer:
7% per year
Explanation:
The amount invested in the calculator was $400. The future value after six years is $600. That rate of return that results in this investment is determined by:
[tex]FV = PV*(1+r)^t\\600=400*(1+r)^6\\1+r = \sqrt[6]{1.5}\\r=0.07 = 7\%[/tex]
The rate of return on the invest is roughly 7% per year.