Calculation in code behind

Question

Chauffeur service cost $30. It is an option to user whether they want the service or not. When they already select car, and day of rental, I store it in session.

Answer 1

totalValue = int.Parse(Session["price"].ToString()) * int.Parse(Session["day"].ToString()) + ShowFerInUse ? 30 : 0;

This way you can use iif equivalent in c# and do ShowFerInUse at same time.