Anyone willing to help me plz i really need it

Cameron has a balance of $10,200 on his credit card. He threw the card away so he can never use it again. He has 3.5 years to pay off the balance. The interest rate on his card is 21%.

At the end of the 3.5 years, how much money in interest alone will Cameron have paid? (just put the numerical value, no $ sign)

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