WHAT CAN BE SEEN ONCE A MOMENT TWICE A MIN RIDDLES WITH ANSWERS TO SOLVE - PUZZLES & BRAIN TEASERS

Let the hourglass with 7 minutes timeframe be x and the hourglass with 11 minutes timeframe be y.
Turn x and y together.
After seven minutes, turn x.
After 11 minutes, turn x again.
Now it will take 4 minutes for x to stop.
At that moment, you would have calculated 15 minutes. Did you answer this riddle correctly?
YES  NO  

Burn one candle from both the ends and simultaneously burn the other candle from just one end. In half an hour, the first candle would have been burnt fully and the second one would have been burnt half. Now light the other end of the second candle as well. In this way, the second candle will take only half the time (30/2 = 15) to burn fully.

Thus, you will have measured forty five minutes. Did you answer this riddle correctly?
YES  NO  

This problem can be best solved using the pigeonhole principle.

The argument will go like this:
Assume that all the non-bald people in NYC have different number of hairs on their head. The population is about 9 million and let us assume that there are 8 million among them who are not bald.

Now, those 8 million people need to have different number of hairs. On an average, people have just 100, 000 hairs on their head. If we keep on assuming that there is someone with just one hair, someone with two, someone with three and so on, there will be 7, 900, 00 other people left who will have more than 100, 000 hairs on their head and need different number of hairs.

Now, as per this assumption, if we keep increasing one hair for each person, to make everybody hair different in numbers, we will come across someone with 8, 000, 000 hairs. But that is practically impossible (even 1, 000, 000 is impossible). Thus there must be two people who are having same number of hairs. Did you answer this riddle correctly?
YES  NO  

They were at the fitness center the whole time. They ran and cycled on exercise equipment. Did you answer this riddle correctly?
YES  NO  

A pair of shoes Did you answer this riddle correctly?
YES  NO  

In 15 minutes. After five Did you answer this riddle correctly?
YES  NO  

17 mins.

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.

Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.

1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 mins Did you answer this riddle correctly?
YES  NO  

Snow. Did you answer this riddle correctly?
YES  NO  

Gravity Did you answer this riddle correctly?
YES  NO  

The kid filled a glass of water and held it over his head for 10 minutes. Did you answer this riddle correctly?
YES  NO  

The murderer was counting the windows to see which floor the old woman was on. He is coming to kill her. Did you answer this riddle correctly?
YES  NO  

The wife is a photographer.

She shot a picture of me , developed it, and hung it up to dry. Did you answer this riddle correctly?
YES  NO  

The teller used the mute button on the phone so her mother only heard "Emergency... Call... Help." This is how she knew to call the police. Did you answer this riddle correctly?
YES  NO  

The hour hand will have moved one-fourth of an hour; therefore, there will be 7.5 degrees between the two hands. Did you answer this riddle correctly?
YES  NO  

Book Did you answer this riddle correctly?
YES  NO