EXPLANATION
Let's see the facts:
Time [Autorepair] Rate
6 3.5
12 4.0
18 4.25
Jin Borrows= $3,670 plans to pay off in 18 months.
Jin Owe= unknown
So, multiplying 3,670 by the 18 months rate, in decimal form, give us the owe as shown as follows:
3,670 x (rate in decimal form--> rate/100)= Simple interest
So, the answer is:
3,670 x (4.25/100) = 3,670 x 0.0425 = 155.97
The simple interest is $156.00