Ralph sold brownies for $0.12 a piece in order to earn money to buy baseball cards. if the cards cost $0.36 per pack, and if ralph had no money left over after buying them, what is the least number of brownies he must have sold

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?