What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

In a boat, the father of a sailor's son is sitting with the son of the sailor. However, the sailor is not present on the boat.

Can this even be possible?

Before Mount Everest was discovered, what was the highest mountain in the world?

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?

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

which number am I?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

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 "?".

What do you see in the given picture?