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?

Solve the mathematical equation in the picture below.

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.

If an electric train is travelling south, then which way is the smoke going?

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

What number when divided in half becomes zero?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.