As noted above make sure you convert the units appropriately first or use our speed calculator which does that automatically. So the average speed from A to D is 20 miles per hour. Hence the correct option here is C 48 kmhr.
The formula for average speed also called average velocity in physics and engineering is.
Average speed total distance total time Typical units are kilometers per hour kph miles per hour mph meters per second ms and feet per second fts. Speed gives only a quantitative idea about how fast or how slow an object is moving. Average speed vs Average velocity Average speed what this calculator computes and average velocity are not necessarily the same thing though they may coincide in certain scenarios. FracM0L1T0M0L0T1M0L0T-1 Therefore the dimensional formula of speed M 0 L 1 T-1.