I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name 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?

Find the number of squares in the below picture

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

What is the largest number you can write with just 3 digits?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

Can you find the key in the picture below?

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?