How many triangles can you find in this given picture?

What has many keys but can’t open a single lock?

Solve this riddle by finding the odd one out from the rest.

I’m tall when I’m young, and I’m short when I’m old. What am I?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Which number should replace the question mark?

People are waiting in line to board a 100-seat aeroplane. Steve is the first person in the line. He gets on the plane but suddenly can't remember what his seat number is, so he picks a seat at random. After that, each person who gets on the plane sits in their assigned seat if it's available, otherwise, they will choose an open seat at random to sit in. The flight is full and you are last in line. What is the probability that you get to sit in your assigned seat?

Why are all black people so quick ?

What has lots of eyes, but can’t see?