Trevor deposits 1500 in a simple intersect account that pays 4.3% interest annually. After 15 years how much total money would be in the account

Ireally need ! if a musician uses his credit card to pay for a new violin that costs $2,900 and does not pay on it until the second month, what will the 3.35% monthly interest charge be at the end of the first month? show your work or explain how you got your answer.