At an instant when a particle of mass 80 g has a velocity of 25 m/s in the positive y direction, a 75-g particle has a velocity of 20 m/s in the positive x direction. What is the speed of the center of mass of this two-particle system at this instant?

a. 16 m/s
b. 45 m/s
c. 23 m/s
d. 20 m/s
e. 36 m/s