Answer:
In 4 years Joe would have to pay $1,680 in simple interest.
Explanation:
So first of all you want to start by finding what P, r and t would be.
P = Principal amount ($$)
r = interest rate (%)
t = time
Once I found all of those I put them into the equation (l = Prt) and solved. That is how I came up with my answer. Check the screenshot provided to see what P, r and t would be and to see all my work! :)
Have a great day!