You want to short sell $100$ shares of PQR using a $60\%$ margin. The maintenance margin is $30\%.$ The current price of $PQR$ is $$40.$ How much money did you have to invest today? What price will trigger a margin call? What is the overall rate of return on your investment if the stock is selling at a price of $$48$ in $1$ year? What is the overall rate of return on your investment if the stock is selling at a price of $$34$ in $1$ year?