A car runs first 275 km at an average speed of 50 km/h and the next 315 km at an average speed of 70 km/h. What is the average speed (in km/h) for the entire journey?

Answer: Option C

Time taken to cover 275 km = $$\frac{275}{50}$$ h = 5.5 h
Time taken to cover 315 km = $$\frac{315}{70}$$ h = 4.5 h
Average speed of entire journey
$$\begin{array}{rl}& =\frac{\text{Total distance}}{\text{Total time taken}}\\ & =\frac{590}{10}\\ & =59\text{ Answer}\end{array}$$