Zara has forgotten her 4-digit PIN code. She knows the first digit is a factor of 20 and the 4 digits make a number divisible by 2.
How many different sets of 4 digits could it be?

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?