Petrolyn motor oil is a combination of natural oil and synthetic oil. It contains 4 liters of natural oil for every 5 liters of synthetic oil. In order to make 711 liters of petrolyn oil, how many liters of synthetic oil are needed?

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?