Kara and steven are biking around a 1,800 kilometer path. they start biking from the same place, at the same time, and in the same direction. kara bikes at a speed of 15 km/h and steven bikes at a speed of 30 km/h. how long will it take before steven and kara will be at the same place of the path next time?

This is the concept of speed, distance and time:
Time taken before the cyclist are on the same sport will be found as follows:
time=distance/(relative speed)
distance=1800 km
given that the cyclist will be riding towards the same side, then
relative speed=(Steve's speed-Kara's speed)=30-15=15 km/h
thus time taken will be:
time=1800/15
=120 hours