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

Replace the question mark with the correct number in below Picture:

What is common among 11, 69, and 88?

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

Can you replace the question mark with the correct number?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

There are three identical triplets sisters. Demi is the oldest of them all and she always speaks the truth. Diana is the next one who is a liar always. Drew, the youngest of them all speaks both truth and lies randomly.

On a rainy day, a family friend Victor visited them. Since there were starkly identical, he was not able to recognize them. Thus to clarify, he asked one question to each one of them.

He started with the one standing on the left and asked, 'Which sister is in the middle of you three?' She answered, 'That's Demi.'

Then, he asked the one standing in the middle, 'What is your name?' She answered, 'I am Drew.'

Finally, he asked the one standing on the right, 'Who is standing in the middle?' She answered, 'She is Diana.'

Victor was left baffled. He asked the questions three times and received different answers every time.

Can you tell who was who?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

Can you find out the total number of triangles in the given figure?

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.