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!