There are 7 keys in each octave (C,D,E,F,G,A and B) so it would make sense to divide 52 to 7.
52/7=7 octaves and 3 extra kets
-2x+9. just distribute a -1
Percentage of depreciation of the car that Marie bought = 15%
Present value of the car = 13000
Let us assume that the value of the car at the time of buying = x
So
The percentage valuation of the car now = (100 - 15) percent
= 85 percent
Then
(85/100) * x = 13000
85x = 13000 * 100
85x = 1300000
x = 1300000/85
= 15294.12
So the actual cost of the car is 15294.12. I hope the procedure is clear enough for you to understand.