SOLUTION: This is the question I'm having problems with... Suppose P dollars in principal is invested in an account that earns interest annually. If after t years the investment grows to A

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Question 135290: This is the question I'm having problems with...
Suppose P dollars in principal is invested in an account that earns interest annually. If after t years the investment grows to A dollars, then the annual rate of return, r, on the investment is given by
r = A/P^1/t -1
Find the annual rate of return on $7,000 which grew to $12,200 after 5 years.
Round your answer to one decimal place.
I filled in the equation with:
r= 12200/7000^1/5 -1
I cancelled out the zeros to get r=122/70^1/5 -1
I'm unsure where to go from here. Thanks.
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
You've done all the hard work. Nice job.
r=%28122%2F70%29%5E%281%2F5%29+-1
r+=+1.743%5E%281%2F5%29+-+1+
r+=+1.743%5E0.2+-+1
r+=+1.1175+-+1+
r+=+0.1175
So r = 11.75%, that's a nice return