Correct Answer - Option 2 : 48 km/hour

**Given:**

Total Distance cover = 78 + 50 = 128 km

Total time taken = 90 + 70 = 160 minutes = \(160\over 60\) hours

**Formula use:**

Average speed = Total Distance Travelled / Total Time taken

**Calculation:**

Average speed = \(128 \over {160\over60}\)

Average speed = \({128 \over 160} ×60\)

Average speed = 48 km/hour

Therefore, the average speed of the car is 48 km/hour.

Hence, the correct answer is **48 km/hour**.