Use the following information for the next $4$ questions.

You sold short $400$ shares of common stock of XYZ Corporation at $$50$ per share. The initial margin is $60\%$ and that the maintenance margin requirement is $25\%.$

How much was your initial $($margin$)$ investment?

If the stock price goes up to $$65,$ how much equity do you have in your account?

If the stock price goes up to $$65,$ what is the actual percentage margin of your account?

How far could the stock price go up before you would get a margin call?