Graphs in practical situations — travel graphs and kinematics

Writing $\text{distance} = \text{speed} \div \text{time}$ instead of $\times$, or dividing the wrong way round.

$9$ h $36$ min is $9.6$ h (since $36 \div 60 = 0.6$), not $9.36$. Convert minutes to a fraction of an hour first.

A point was read as $(1, 4)$ because it was "1 square along, 4 squares up" — but each square was not one unit, so the true values were different. Always use the axis scale.

Average speed for a whole journey is total distance $\div$ total time, NOT the average of the individual leg speeds. A there-and-back $15$ km trip is $30$ km total, so use $30$, not $15$.

On a speed–time graph the GRADIENT is the acceleration and the AREA is the distance. Using speed $\times$ time for an accelerating (triangular) phase, or the gradient when distance is asked, is a frequent mix-up.