Which expression represents speed?

Which expression represents speed?

• A. Distance/Time
• B. Time/Distance
• C. Distance Times Speed
• D. Speed Plus Time

Answer: (A)

Speed is the rate at which something moves: how far it travels in a given amount of time. That means it’s expressed as distance divided by time. So the expression distance/time matches the idea of speed, giving units like meters per second or kilometers per hour. If you use time divided by distance, you get the inverse idea—how long for each unit of distance—which is not speed (it’s the inverse of speed, sometimes called pace). Multiplying distance by speed would produce a quantity with different units (distance squared per time), not a simple rate of motion. Adding speed and time combines two different kinds of quantities, which doesn’t describe a rate either.

Speed is the rate at which something moves: how far it travels in a given amount of time. That means it’s expressed as distance divided by time. So the expression distance/time matches the idea of speed, giving units like meters per second or kilometers per hour.

If you use time divided by distance, you get the inverse idea—how long for each unit of distance—which is not speed (it’s the inverse of speed, sometimes called pace). Multiplying distance by speed would produce a quantity with different units (distance squared per time), not a simple rate of motion. Adding speed and time combines two different kinds of quantities, which doesn’t describe a rate either.