Joe borrowed $9,000 from the bank at a rate of 7% simple interest per year. How much interest did he pay in 5 years?

Joe would be paying $700 in 5 years time.
Explanation:
From the Formula:
I = Pin
where : I - interest
P - principal
i - the interest rate
n - the number of years
I = Pin, plug in the given data as provided in the problem.
P = $2,000
i = 0.07 per year
n = 5 years
I = ($2,000)(0.07/year)(5 years)
= ($2,000)(0.07)(5)
= $700