$1)$You are trying to save up money for the down payment on a house. You know that you want to have $$40,000$ in exactly four years. How much money should you put each month into an account that earns $2\%$ monthly interest to achieve your goal?

$2)$Your monthly mortgage payment is $$2,400.$ If you have a fixed monthly interest rate of $1\%$ and a loan term of $30$ years, how much did you initially borrow to purchase your house?

$3)$Daniel set up a college fund for his daughter on the day she was born. If he puts $$1,200$ per year in a savings account that has an annual interest of $10\%,$ how much money will be in the account when his daughter turns $18?$