A $5-$year convertible bond with a coupon rate $6\%$ can be converted into $20$ shares of common stock.

This bond has a yield of $7\%.$ Its current stock price is $$40$ per share and it is expected to grow at $5\%$ per

year. Approximately when will the bondholders on this convertible bond will convert this bond into $20$

shares of common stocks? Please support your answers with calculations. $(6$ points$)$