A full mechanical reasoning test: 25 questions in 20 minutes, 48 seconds each, on gears and belts, levers, pulleys, springs and pressure. No calculator, and the arithmetic is small.
Most questions need one rule. Gears in a chain alternate direction, and speed changes with the ratio of teeth. A crossed belt reverses direction. A lever balances when weight times distance is equal on both sides. Each supporting rope in a pulley shares the load.