If eleven plus two equals one, what does nine plus five equal?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

A man was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?

A man has to get a fox, a chicken, and a sack of corn across a river.

He has a rowboat, and it can only carry him and one other thing.
If the fox and the chicken are left together, the fox will eat the chicken.
If the chicken and the corn are left together, the chicken will eat the corn.

How does the man do it?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

I shave every day, but my beard stays the same. What am I?