What does this mathematical rebus means ?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

What does below rebus means ?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Kohli and Dhoni decided to have a paintball match.
Kohli told Dhoni, "Sir it is not right as you got thrice the paintballs I have".

Dhoni instantly gives Kohli 10 hit paintballs.
Kohli replied, "Sir, I believe you still have twice the paintballs than I have".

Dhoni gives "?" more paintballs to Kohli.
Kohli replied, "Sir it is even now, Let us have a match".

What is "?".

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.

Can you count the number of quadrilaterals in the picture below?