Motion — practice question

A train sets off from a station and covers $60\,\text{km}$ in a time of $20\,\text{minutes}$. What is the train's average speed?

• A$3.0\,\text{m s}^{-1}$
• B$5.0\,\text{m s}^{-1}$
• C$50\,\text{m s}^{-1}$
• D$60\,\text{m s}^{-1}$