A motorist travelled between two towns, which are 65 km apart, in 2 hours and 10 minutes. Find the speed in metres per minute.

### Concept & Specific Unit Conversion The problem asks for speed in a non-standard unit: **metres per minute**. Therefore, the most efficient approach is to convert the total distance into metres and the total time into minutes before dividing. $$ \text{Speed} = \frac{\text{Distance in metres}}{\text{Time in minutes}} $$ ### Step-by-Step Solution * **Given:** Distance = $65$ km, Time = $2$ hours and $10$ minutes. * **Convert Distance:** Since $1$ km = $1000$ m, Distance = $65 \times 1000 = 65,000$ metres. * **Convert Time:** Since $1$ hour = $60$ minutes, $2$ hours = $120$ minutes. Total Time = $120 + 10 = 130$ minutes. * **Calculate Speed:** * $\text{Speed} = \frac{65000}{130}$ * Cancel out the trailing zeros: $\frac{6500}{13}$ * We know $13 \times 5 = 65$, so $13 \times 500 = 6500$. * $\text{Speed} = 500$ metres per minute. ### Exam Strategy & Shortcut Convert exactly into the units requested by the prompt directly, rather than converting to standard m/sec first and then scaling up to m/min. This prevents multi-step conversion errors and keeps the arithmetic cleaner. ### Common Pitfall A common error is converting the time to a pure hour decimal incorrectly (e.g., writing $2$ hours $10$ minutes as $2.1$ hours instead of $2 \frac{10}{60}$ hours) or converting the final answer into meters per second out of habit. ### Final Answer Therefore, the correct answer is **500**.