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

THINGS TO REMEMBER:

Question: Write an expression for how much it would cost to park for 3d hours on a holiday during peak hours.

3d × 2  or  3d + 3d

Explanation: This is because during holidays the amount of d doubles. However since this is on a holiday DURING peak hours it would be 3d × 2

Question 2: 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?

$15

Explanation: Since d represents dollars we would multiply 2.50 times 3 which would give us 7.5 then we double this since it is during holidays giving us $15

NOTE: I AM SO SORRY IF THIS IS WRONG AND I MISSED SOMETHING. IF IT IS WRONG THEN PLEASE MAKE SURE TO TELL ME SO I CAN FIGURE OUT WHAT I MISUNDERSTOOD

Again I'm sorry but I hope I helped a little bit.    

4 and 5)16.97 or 12√2

6)15.59 or 9√3

7)y = 15.59 or 9√3     x =27

8)17.80