I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

What does below pictogram mean?

How many triangles are there on the puzzle below?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

Which flower has two lips?

What has many keys but can’t open a single lock?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

What word is pronounced the same if you take away four of its five letters?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?