If the intermediate gear is removed from that same three-gear drive, the gear ratio will be

• A. 3
• B. 4
• C. 5
• D. 6

Answer: (C)

In a multi-gear drive, the overall speed ratio is determined by the teeth on the first gear and the last gear. The middle gear just transfers motion between the two stages, and when you multiply the stage ratios (input to intermediate and intermediate to output), the middle gear’s effect cancels out. So the overall ratio depends only on the first and last gears.

If the setup is such that the first-to-last gear combination yields a five-to-one reduction, removing the intermediate gear leaves that same first-to-last relationship intact. That’s why the resulting gear ratio is five. The other numbers would require different first or last gear sizes, which isn’t the case here.