Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

John was piloting a plane behind a car but was never able to overtake it. Why?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

I am the fastest animal but cannot climb the tree. What am I?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

Can you identify the hidden rebus in the image below?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

On a bus, there is a 26-year-old pregnant lady.
A 30-year-old policeman.
A 52-year-old random woman.
And the 65-year-old driver.

Who is the youngest?