Need help with some practice problems in Portfolio Management

Hello guys,

I have some difficulty solving Portfolio Management Reading 42 Portfolio Risk and Return: Part 1 Utility fucntion problemas (19-23). I would much appreciate if you cn explain solution of those problems. I have tried several times and can’t seem to get the right asnwer and can’t understand book answers aswell. So if you have got some time please explain the solutions of those problems.

Thanks in advance.

Best Regards,