The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

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?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

What is the longest word in the dictionary?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?