You have the correct answer
Interest rate = 21.5%
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Work Shown:
i = P*r*t .... simple interest formula
i = simple interest
i = 2075-1000 = 1075
P = 1000 = amount borrowed (principal)
r = unknown interest rate
t = 5 = time in years
So,
i = P*r*t
1075 = 1000*r*5
1075 = 5000r
5000r = 1075
r = 1075/5000
r = 0.215
r = 21.5%