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?

I’m tall when I’m young, and I’m short when I’m old. What am I?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

Who can jump higher than a Mountain?

Andrew sees a very rare bird named "Ruppell's vulture". Soon Andrew was dead. Can you explain the mystery, Mr. Sherlock?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?

You need to arrange three 7 and mathematical symbols to form number 1?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

There is so small cabin inside a deep forest.
All the forest burned out to worst possible but the inside of the cabin is still the same.
However all the person inside the cabin die.

How come ?

What number comes next in the series?

5 15 5 18 5 24 14 20 _