You can see five identical squares made with blue matchsticks in the given figure. You have to make them six identical squares instead. To do that, you are only allowed to move three matchsticks. How will you achieve the desired result?
4 + 9 = 1
The trick to solve is to assume the first number as the time in AM and the second number is the number of hours you have to add to it. You'll find the time in PM when you do that.
* They have only one torch and the river is too risky to cross without the torch.
* If all people cross simultaneously then torch light wont be sufficient.
* Speed of each person of crossing the river is different.cross time for each person is 1 min, 2 minutes, 7 minutes and 10 minutes.
What is the shortest time needed for all four of them to cross the river ?
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 minutes. 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)
We know that Christanio Ronaldo tells the truth on only a single day of the week. If the statement on day 1 is untrue, this means that he tells the truth on Monday or Tuesday. If the statement on day 3 is untrue, this means that he tells the truth on Wednesday or Friday. Since Christanio Ronaldo tells the truth on only one day, these statements cannot both be untrue. So, exactly one of these statements must be true, and the statement on day 2 must be untrue.
Assume that the statement on day 1 is true. Then the statement on day 3 must be untrue, from which follows that Christanio Ronaldo tells the truth on Wednesday or Friday. So, day 1 is a Wednesday or a Friday. Therefore, day 2 is a Thursday or a Saturday. However, this would imply that the statement on day 2 is true, which is impossible. From this we can conclude that the statement on day 1 must be untrue.
This means that Christanio Ronaldo told the truth on day 3 and that this day is a Monday or a Tuesday. So day 2 is a Sunday or a Monday. Because the statement on day 2 must be untrue, we can conclude that day 2 is a Monday.
So day 3 is a Tuesday. Therefore, the day on which Christanio Ronaldo tells the truth is Tuesday.
This is a classic chess puzzle and considered to be one of the hardest puzzles in history.
As shown in the picture below, White army is arranged in a classic chess board. You need to add black army i.e
in such a way that not a single piece of either color is under attack.
There are a hundred statements.
1st person says: At least one of the statements is incorrect.
2nd person says: At least two of the statements is incorrect.
3rd person says: At least three of the statements are incorrect.
4th person says: At least four of the statements are incorrect.
100th person says: At least a hundred of the statements are incorrect.
Now analyze all the statements and find out how many of them are incorrect and how many are true?
The 100th statement for sure is incorrect because it says that at least 100 of the statements are incorrect.
Suppose if that is correct, then 100 statements cannot be true.
This suggests that the 100th statement is incorrect and that the first statement is true.
Similarly 99 statements cannot be true because if they were true, then two statements would become correct i.e. the 1st and the 99th.
But the 99th statement says that at least 99 are incorrect.
This suggests that the 99th statement is incorrect and that 2ndone is true.
If we keep analyzing is the same way till the end, we will find out that only the first fifty statements are true and all the remaining ones are incorrect.
Two world's famous prisoners 'Colditz' and 'Pascal' are locked in a cell.
They plan to escape from the cell.
They noticed there is an open window at 40 feet above the ground level.
Both of them tried very hard but are never able to reach there.
Then both of them decided to plan to escape by a tunnel and they start digging out.
After digging for just 5 days, Colditz and Pascal comes out with the much more easier plan than tunneling and they escaped.
A person has uncovered a secret that was a mystery for ages. He transfers the data into his hard drive and encrypts the drive with a password. Then, he writes a line on a paper to remember the password.
The line says 'You force heaven to be empty'.
Can you decrypt the line to reveal the password if you know that the password is seven characters long that comprise of just letters and numbers?