Please explains these two problems step by step not using excel or calculator

If you deposit money today in an account that pays 6 5% annual interest, how long will it take to double your money? You have $42, 180.53 in a brokerage account, and you plan to deposit an additional $5,000 at the end of every future year until your account totals $250,000. You expect to earn 12% annually on the account. How many years will it take to reach your goal