First, find the number of guitarists. 5/8*64=40.
Now, create an equation. x + 4x = 40
5x = 40
x= 8
There are 8 jazz solos and 32 classical solos.
The equation is a scientific law, Newton's Law of Gravity,

This is a pretty bad question. Newton's Law of Gravity is a mathematical model of gravitation, originally a theory, verified by observation, and now superseded by the General Theory of Relativity.
C is probably the best answer to this poor question.
Using the cube formula for volume I got V=3.38cm^3