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

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Can you find out the remainder when 3^300 is divided by 5?

Tell me the Hindi name of a Vegetable which if we remove 1st word will become a precious Stone and by removing the last word it will become a sweet eatable.

How many triangles are there on the puzzle below?

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

Different lights make me strange by changing me into different sizes. What am I?

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

which number am I?

There is so small cabin inside a deep forest.
All the forest burned out to worst possible but the inside of the cabin is still the same.
However all the person inside the cabin die.

How come ?

Four men were in a boat on the lake. The boat turns over, and all four men sink to the bottom of the lake, yet not a single man got wet! Why?