8, 24, 40

Large driver gear makes the merry go round go fast. 3 to 5

Small driver gear makes the merry go round go slow. 15 turns

The gear on the motor is the driver.
The merry go round with the 8 tooth follower goes faster than the one with the 40 tooth gear.

Odd number of gears has the merry go round go in the same direction.

Even number of gears has the merry go round go in opposite directions.
Different size idler gears do not change speed.