A man travels from P to Q at a speed of 50 km/h and then from Q to R at a speed of 60 km/h, where Q is between P and R. The ratio of distances PQ and QR is 1 : 2. He travels from R to P at a speed of 45 km/h. What is his average speed (in km/h) for the whole journey?
- A48
- B52
- C54
- D50
Correct answer: D