The tachometer displays engine speed multiplied by what?

Answer: C — 100

The tachometer displays engine speed as a multiple of 100 RPM (Revolutions Per Minute). This means that when the engine is idling at 800 RPM, the tachometer reading will show 800, indicating the actual engine speed in hundreds. Therefore, if the correct answer is stated as 100, it is simply reflecting the scale on which the engine speed is expressed. Understanding this scaling is crucial for operators, as it allows for an easier interpretation of engine performance and helps in monitoring engine conditions effectively. Knowing the relationship between the tachometer reading and the actual engine speed aids in maintaining optimal operational conditions and can prevent potential engine damage from excessive RPMs.