The question you are asking seems to be a basic question of physics.
the linear velocity of any point rotating about a fixed axis with an angular velocity of is where r is the distance between the point and axis.
The conveyor belt must be moving at the same speed as the rollers (at the point of contact ) therefore where r is the radius of the rollers i.e. 0.08 m. remember is the rate of change of the angle . the rollers turn 2 revolutions in a second .therefore they turn at the rate of per second .