The more it dries, the wetter it becomes. Can you tell what it is?

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

What four weights can be used to balance from 1 to 30 pounds?

If an electric train is travelling south, then which way is the smoke going?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

When does a USA Potato change its nationality?