A speedometer reads $60{\text{ km h}}^{-1}$ with a systematic error of $pm1$ and a random error of $pm0.5{\text{ km h}}^{-1}$. What is the possible range of the true speed of the vehicle?

Step-by-step solution

1. Compute systematic error: $1$ of $60=0.6$ km h${}^{-1}$
2. Combine systematic and random errors: $0.6+0.5=1.1$ km h${}^{-1}$
3. Subtract from reading: $60-1.1=58.9$ km h${}^{-1}$
4. Add to reading: $60+1.1=61.1$ km h${}^{-1}$

Concept tested: Error propagation

Published 4 October 2026 · How this solution was prepared and checked