2.5 hours divided by 42.5km .
Hi there,
Your question is little bit incomplete but as you have mention time and distance. I am assuming you have to calculate speed.
Time = 2.5 hours
Distance= 42.5 km
Speed= Distance/Time
= 42.5 km/ 2.5 hours
=17 km/ hour.
Hence sped is 17 km/ hour which means 17 km is covered in 1 hour.
Hope it helps you
Good luck!