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?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Find out the missing number in the picture attached:

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

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

A mother bought three dress for her triplets daughters(one for each) and put the dresses in the dark. One by one the girls come and pick a dress.
What is the probability that no girl will choose her own dress?

4 fathers, 2 grand-fathers and 4 sons went to watch the movie.What is the minimum number of tickets they need to buy ?

Count the number of triangles in the picture below:

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.