What is the Surname of Barbie Doll?

I’m tall when I’m young, and I’m short when I’m old. What am I?

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?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

What English word has three consecutive double letters?

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?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?