Can you convert the number zero(0) into a positive number using just one mathematical operator ?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

Which tank will fill first?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?