A Wave Is Given by the Equation $y ( x , t ) = 4.0 \cos ( 6 \pi x - 10 \pi t )$

Multiple Choice

A wave is given by the equation $y ( x , t ) = 4.0 \cos ( 6 \pi x - 10 \pi t )$ m. The speed of the wave is

A) 20 m/s.
B) 15 m/s.
C) 12 m/s.
D) 3/5 m/s.
E) 5/3 m/s.