You can put this solution on YOUR website! Is it compound or simple interest? I will assume it's compound and that it compounds once per year. If it's something else you can send me an email and I'll send you the answer
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Principal(1+rate)^time = Amount
8400(1+0.032)^8 = 8400(1.032)^8 = 8400(1.2866) = 10807.44