Hi, I have a question with problem 1 b) and c).

1 b), this question is asking "check whether current $1.5 price is profit maximizing." In the lecture, professor gave us equation "P=MC*(Ep/1+Ep)" I would like to use this mark up equation to check this is optimal point or not. Can you advice me?

1 c). I don't understand how I can reach out this solution. Can you elaborate a little bit for me?

Thank you!