Physics ( Predict when two cars are gonna meet )

If you are not confident in the understanding of one-dimensional motion, you can strengthen them up in this chapter.

https://www.khanacademy.org/science/physics/one-dimensional-motion 

Below is the solution I obtained:

*for the different speeds of the cars, I simply put in any 2 different values. If the values are different from what you are given, you can change it and the method of solving will be the same, don't worry.