A car takes 10 hours to complete a journey at a speed of 42 km/h. To cover the same distance in 7 hours, by how much should the speed of the car be increased?
- A. 12 km/h
- B. 15 km/h
- C. 18 km/h
- D. 20 km/h
- 18 km/h
Please select one of the options to reveal the correct answer.