Correct Answer - Option 1 : 7.5
Given:
Distance between P and Q = 30km
Formula:
Average speed = total distance/total time
Calculation:
Time taken by A = 2 hr + 48 min = 2 + 48/60 = 14/5 = 2.8 hours
Distance of level road = 18km
Time taken to travel level road = 18/15 = 1.2 hours
Time taken to travel uphill road = 2.8 - 1.2 = 1.6 hours
Distance of uphill road = 30 - 18 = 12 km
Speed to travel uphill road = 12/1.6 = 7.5 kmph
∴ Average uphill road speed is 7.5kmph.