Question

The beginning balance of Keyshawn's savings account for the month of September was $3900, and it remained this way for the first 11 days of the month. On September 12, Keyshawn made a withdrawal of $700, so his balance changed, and it remained the same for a total of 9 days. On September 20, Keyshawn made a deposit of $1500, so his balance changed again, and it remained the same for a total of 10 days to finish out the month. Keyshawn's savings account has an APR of 3.65%, calculates interest daily, and pays interest at the end of the month. Keyshawn wants to calculate the amount he earned in interest during the month of September.
Part I: What interest rate does Keyshawn's savings account pay per day?
Part II: How much did Keyshawn earn in interest during the first 11 days of September?
Part III: How much did Keyshawn earn in interest during the next 9 days of September?
Part IV: How much did Keyshawn earn in interest during the last 10 days of September?
Part V: How much did Keyshawn earn in interest during the month of September?

Answer 1

Simple or compound interest