If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Our product and our sum always give the same answer. Who are we?

There’s a girl who has a large family. She has an equal amount of brothers and sisters, but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?

What does an Island and the letter T have in common?

If you say my name, I will no longer exist. What am I?

You can see it everyday, But cannot touch it at will. What is it?

An octopus has 8 legs. A hippogriff has 6 legs and 2 pairs of wings. A sphinx has 6 legs and one pair of wings. Now we have all 3 kinds and a total of 18 insects in a cage. We have a total of 118 legs and 20 pairs of wings. How many insects do we have of each kind?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

Count the number of triangles in the given picture.