World's Hardest Riddles With Answers

This puzzle is known as the Turan Brickyard Problem and is a classic one. There is no way that they can be connected without crossing the lines in 2 dimension. However, you can do it if you place the scene in a 3d workplace. See to the figure to understand better.

Let us take this one step at a time.

Let us calculate the probability that Anna and Brian have the same number in their mind.
101/125

Now, there's a 1/5 chance that the numbers will be same and 4/5 chance that the numbers are different.

Let us now include Christy in this data. There can be two cases.
1) Anna and Brian have the same number. In that case, Christy will have only one number to compare.
2) Anna and Brian did not have the same number. In that case, Christy will have two numbers to compare to.

For the first case, the probability will be 5/25. This is if Anna and Brian did have the same numbers.

But if Anna and Brian did not have the same numbers, there is a 2/5 probability that Christy is having the same number (this is because Christy gets to match her number with both Anna and Brian). In that case, we can simply multiply the probabilities.
4/5 * 2/5 = 8/25

Otherwise, if Christy is not having the same number, the probability is 3/5. Now multiplying with the previous chain:
4/5 * 3/5 = 12/25

Now, we can include Drake in our calculations. If we follow the path where Drake's number matches with Anna and Brian, the probability will be 25/125.

Now let us join that with Christy's probability. If Christy's number matches with Anna and Brian and Drakes' number also matches, then the probability will be:
4/5 * 2/5 = 40/125

If Christy's number does not match with Anna and Brian but Drake's number matches with Christy's, the probability will be:
4/5 * 3/5 * 3/5 = 36/125

But if Christy's number does not matches with Anna and Brian and even Drake's does not matches with Christy, then the probability will be:
4/5 * 3/5 * 2/5 = 24/125

Now, we have to tell the probability when all the four friends have same numbers, so we will just add up the probability where all the numbers matches:

25/125 + 40/125 + 36/125 = 101/125.

CITIZENSHIP

If we are considering an ideal case and we have to calculate the maximum score, we will assume that the batsman hits six on every ball. But then, at the end of every over, the strike will change. But we have to make sure, he gets to play maximum number of balls to score maximum runs. Thus, the batsman will hit six in first five balls and will choose to take 3 runs in the last ball so that he retains the strike in the following over.

Total runs per over in that case = 6 * 5 + 3 = 33.

But in the last over (50th over), he don’t have to worry about keeping the strike and thus, he will hit six even on the last ball. Therefore, the maximum runs that a batsman can score:

33 * 49 + 6 * 6 = 1617 + 36 = 1653

If you start arranging the numbers alphabetically, the numbers 8 (eight) will come first and the number 2202 (two thousand two hundred and two) will come at last.

50%

The next toss of the coin is not dependent upon the previous ten tosses. Thus, the probability is 50 percent only.

L8

This is a bit tricky questions. To solve you must look at the series upside down. It is actually
91, 90, 89, 88, __, 86

So we need 87 in the place of blank. To achieve 87 in an upside down position, the correct answer will be L8.

Thus, the missing item in the series is L8.

The back seat of the last coach will be the best. The reason is because, the train will be accelerating after the stop and thus, it will be much faster when the back of the train enters the tunnel than when the front of the train enters. Thus you will have to spend less time in the tunnel.

The number 40 (Forty) is the only number which when written in English has all the letters in the same order as in the alphabets.

It is possible if you are using Roman Numerals.
9 = IX
10 = X
11 = XI
Now it is all possible.