so whatd you get for upper/lower bounds or a/b?

Thanks :D I managed to solve it! I was making a mountain out of a molehill I realized afterwards.

invert the inside of P() to get P(a > beta/2n Xbar> b)

then P(stuff1 > beta > stuff2) 

invert the inside of P() to get P(a &gt; beta/2n Xbar&gt; b)

then P(stuff1 &gt; beta &gt; stuff2) 

I managed to figure out all of my homework except the last problem, shown right [here](https://gyazo.com/ca913a8d71695929d31393c381e8ad92). I don't even know where to start, and I'd really like to get this done, so any help would be greatly appreciated!

Exponential Distribution with Scale Parameter