Can you replace the question mark with the correct number?

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?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

Which alphabet letter is a question?

What is the last thing you take off before bed?

Which is Odd One Out and why?

4377

3954

9862

8454

9831

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?