Can you convert the number zero(0) into a positive number using just one mathematical operator ?

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 ?

Find the smallest sentence with all the English alphabet.

What question can you never answer yes to?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

Three friends named Mr. Black, Mr. Yellow and Mr. Green enter a pub on a weekend night. They are wearing either a Black, Yellow or Green shirt.

Mr. Yellow says to them, 'Did you notice that we all are wearing different color shirts than our names?'

To this, the man who was wearing the Green shirt said. 'Wow, thats right.'

Can you identify who is wearing which colour shirt ?