Car X traveled 3d distance in t time. Car Y traveled 2d distance in t time. Therefore, the speed of car X, is 3d/t, the speed of car Y, is 2d/t. Since speed is the distance taken in a given time.
In figure-2, they are at the same place, we are asked to find car Y's position when car X is at line-A. We can calculate the time car X needs to travel to there. Let's say that car X reaches line-A in t' time.

Okay, it takes t time for car X to reach line-A. Let's see how far does car Y goes.

We found that car Y travels 2d distance. So, when car X reaches line-A, car Y is just a d distance behind car X.
Answer:
Reflected ray. A ray of light or other form of radiant energy which is thrown back from a nonpermeable or nonabsorbing surface; the ray which strikes the surface before reflection is the incident ray.
For a neutral atom number of electrons equals number of protons, in other for the net charge of the atom to be zero...
no. of electrons = 12
The units are not consistent - 1 m/s is not the same as 1 km/h.
First thing to do would be to convert from one unit of speed to the other, say km/h to m/s. There are 1000 meters (m) for every kilometer (km) and 3600 seconds (s) for every hour (h), so

So in fact 1 km/h is about 4 times slower than 1 m/s.