You have a 40 inch wheel tow 20 inch wheel to a 5 inch wheel how many revolutions does the 5 inch wheel have to make to make the 49 inch wheel rotate 1revolution?
circumferences vary in the same ratio as the radii.
since 40/5 = 8,
the 5" wheel rotates 8 times for every rotation of the 40" wheel.
extra credit: do they turn in the same direction?