My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

In a school, 280 students studied chemistry, 254 students studied physics and 280 students studied biology.

97 students studied chemistry as well as physics, 138 students studied physics as well as biology and 152 students studied chemistry as well as biology.

73 students studied all the three branches.

Can you find out the total number of students?

1 rabbit saw 9 elephants while going to the river. Every elephant saw 3 monkeys going toward the river. Each monkey had 1 parrot in each hand. How many animals are going towards the river?

Six people park their car in an underground parking of a store. The store has six floors in all. Each one of them goes to a different floor. Simon stays in the lift for the longest. Sia gets out before Peter but after Tracy. The first one to get out is Harold. Debra leaves after Tracy who gets out on the third floor.

Can you find out who leaves the lift on which floor?

I am written with two letters.
I said with the one.
I usually am seen with the two.

Who am I?

This was asked in an interview with Coa-Cola.

The interviewer has given me 100 marbles(50 white and 50 black) and two empty boxes.
He then told me that he will leave the room and i need to place all the marbles in two boxes.

And When he come back, he will draw a marble from any of the two box and if the marble is white I will be hired.

Also
* No box can be empty.
* All 100 marbles must be placed in one of the two boxes.

So what should I have done?

A Child was born in Lahore, Pakistan. Still, the child is not a Pakistani citizen. why?

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

In a holy town, three temples sit in a row identical in almost every manner including a holy well in front of them. A pilgrim comes to visit the temples with some flowers in his basket.

At the first temple, he takes some water from the holy well and sprinkles it on the flowers to wash them. To his astonishment, the number of flowers in his basket doubles up. He offers a few of them at the temple and turns back to visit the second temple.

At the second temple, he again takes some water from the holy well and sprinkles it on the flowers to wash them. Again the number of flowers double up in number. He offers some of them at the temple and turns back to visit the third temple.

At the third temple, he repeats the process and the number of flowers doubles up yet again. He offers all the flowers in the third temple.

Now, the pilgrim offered the same number of flowers in all the temples. Can you find out the minimum number of flowers he must have had initially? How many flowers did he offer to god in each of the three temples?

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?