Okay hear this someone came into my shop and stole $100 without my knowledge they came back to the store and spent $70 in items i gave $30 back how much money did i lose ?

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?