Question

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?

Answer 1

It would take them 120 hours to get to the same point on the path again.

Kara is traveling at half the speed of Steven. Therefore, we Steven finishes his second lap Kara will just be finishing her first lap. They will both be at the starting lap again.

It will take Kara 120 hours to complete the lap. 
1800 / 15 = 120  

(That is a lot of time, do you have the numbers correct?)