What's the only room from which no one can enter or leave

The Federal bank of London is abducted by the robbers. The head of the robbers asked the cashier to empty their money vault to them and when suddenly cashier got a call from her father. To avoid any suspicion, the robber asked the cashier to pick the call and reply her father in the shortest manner possible.

The cashier told her father "Is there an emergency father, Call me when you are free and I will help you in your furnishing" and then the cashier hung up the phone.

After 10 minutes, police arrived at the crime scene.

How did the police know about the robbery?

What's the best place to go shopping in the ocean?

It belongs to you, but other people use it more than you do. What is it?

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?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

I am the fastest animal but cannot climb the tree. What am I?

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?

How many triangles can you find in this given picture?