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?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.” Who is in the painting?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

What begins with T, ends with T, and has T in it?

Count the number of squares in the picture below.

Can you find the mistake in the below statement?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

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?