You divide the distance by the speed: 2468/35=70hr 31mins approx. (70.51hr)
Here's a clue about dimensions: it's in the words we use for speed: miles per hour is a measure of distance and hour a measure of time. Per means divided by, so speed is distance divided by time.
We can write s=d/t so t=d/s, or distance divided by speed. Other examples of dimensions are density=weight/volume (grams/cubic centimetre); unit rate (dollars, euros, GB pounds, etc. per pound weight); fuel consumption (miles per gallon); fuel cost (£ or $ per litre or gallon); etc.