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

I cannot talk, but I always reply when spoken to. What am I?

Jack have ten pairs of black socks, eight pairs of white socks and seven pairs of green socks. Everything is mixed in a draw. As there is no light he were not able to identify the colour of the socks. How many of the socks did he want to take to match one pair

Replace the question mark with the correct number below.

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

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?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

How can you write nineteen in a manner that if we take out one, it becomes twenty?