So firstly, multiply both sides by t: 
Next, add both sides by v0, and your answer will be: 
N+7 - 7 more songs added
n-2 - 2 songs deleted (subtracted)
4n - 4 times more songs than before
n/2 - the number of songs cut in half (divided by 2)
Answer:
28.27 inches
Step-by-step explanation:
circumference of a circle = πd
9π = 28.27