I am white when I am dirty, and black when I am clean. What am I?

Find the value of "a" by solving the maths equation in the picture below:

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

How many sides does a circle have?

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

On a beautiful Sunday morning, You ordered a hot tea to your hotel room and suddenly you remember an important thing that needed to be done right now will take around 3 minutes to complete.
Like most people you like your tea to be hot while drinking so, when should you pour cream in the tea?
1. straight away
2. Just people, you drink the team
3. Its does not matter

It belongs to you, but other people use it more than you do. What is it?

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL