Parking at the posh center costs d dollars per hour during the off hours and an extra $3 per hour during peak hours. During holidays, the basic rate of d doubles. Write an expression for how much it would cost to park for 3d hours on a holiday during peak hours. Then, if the basic off-hours parking rate is $2.50 per hour, how much would a person pay to park for 3d hours in the situation described above?

PLEASE HELP. I WILL GIVE BRAINLIEST TO THE PERSON WHO ANSWERS BOTH PARTS OF THE QUESTION.