Using the student id given above, a = 19 and b = 7
Average speed for the first 54 km = 48+a km/h
Plug a = 19
Average speed for the first 54 km = 48+19 = 67 km/h
Average speed for remaining 86 km = 43-b km/h where b = 7
Average speed = 36 km/h
Average speed of entire journey = total distance / total time taken

Time taken to cover 54 km =
hr
Time take to cover 86 km =
hr
Total time taken = 3.2 hours.
Total distance = 86+54= 140 km
Average speed of the entire trip =
= 43.75 km/ h