How do you calculate rate of change?

How do you calculate rate of change?

• A. (Oldest - Newest) / Change in time.
• B. (Newest - Oldest) / Change in time.
• C. Change in time / (Oldest - Newest).
• D. Oldest - Newest.

Answer: (A)

Rate of change is how much a quantity changes per unit of time. It is defined as ΔQ/Δt, the difference in the quantity divided by the difference in time between two observations. If you compare the oldest observation to the newest, you can subtract in that order for the quantity (Oldest minus Newest) and use the corresponding time difference (Oldest time minus Newest time). Those two differences both carry a negative sign, so they cancel when you divide, producing the same result as the standard form (Newest minus Oldest) over (Newest time minus Oldest time). The important point is to stay consistent with the order of subtraction for both the quantity and the time.

Rate of change is how much a quantity changes per unit of time. It is defined as ΔQ/Δt, the difference in the quantity divided by the difference in time between two observations. If you compare the oldest observation to the newest, you can subtract in that order for the quantity (Oldest minus Newest) and use the corresponding time difference (Oldest time minus Newest time). Those two differences both carry a negative sign, so they cancel when you divide, producing the same result as the standard form (Newest minus Oldest) over (Newest time minus Oldest time). The important point is to stay consistent with the order of subtraction for both the quantity and the time.