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?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

Count the number of balls in picture below:

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

In which direction should the missing arrow point?

The peacock is a bird that does not lay eggs. How do they get baby peacocks?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

John is 45 years older than his son Jacob. If you find similarities between their ages, both of their ages contain prime numbers as the digits. Also, John's age is the reverse of Jacob's age.

Can you find their ages?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?