You are bullish on Tesla. The current market price is $600. You have $30,000 of your own and you borrow $30,000 from your broker at an interest rate of 5% per year and invest $60,000 in the stock. a. What will be your rate of return if Tesla goes up by 30% in the next year? b. Now suppose Tesla stock price starts falling as soon as you buy it, at what point would you get a margin call from your broker if the maintenance margin is 30%?