What does an Island and the letter T have in common?

What does this rebus riddle means ?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

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?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

What is the relationship between these matchstick pictures below?

Find the Odd One Out?
84129
32418
47632
36119
67626
72927

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Which is the rope you never skip with?

Why Wine Glass Stem is so long?