World's Hardest Riddles With Answers

Let us consider the length of the tunnel first; which is 200 miles. Now, the trains are running on the same speed which means that they will collide at the center of the tunnel and will take an hour to reach the center. Now the bird is travelling at a speed of 1000 mph and it is flying for an hour (since the trains will take an hour to collide). Thus the bird will travel 1000 miles in the process.

I spoke with Mia.

Let us assume that Tia is a liar and Mia is a truth teller.
If I asked the question from Mia, the answer will be yes. If I asked the question from Tia, the answer will be no. Thus I must have asked from Mia.

Let us assume that Tia is a truth teller and Mia is a liar.
If I asked the question from Mia, the answer will be yes. If I asked from Tia, the answer will be no. Thus in this case as well, I must have asked from Mia.

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Since the probability of having a girl or a boy is same, half of the families will have a boy first and stop. The other half of the families will have a girl and from half of those families, the second born will be a boy and they will stop while the others will again have a girl. This process will continue.

Suppose the number of couples are N, the number of boys will be N.

1/2 have a boy and stop: 0 girls
1/4 have a girl, then a boy: N/4 girls
1/8 have 2 girls, then a boy: 2*N/8 girls
1/16 have 3 girls, then a boy: 3*N/16 girls
1/32 have 4 girls, then a boy: 4*N/32 girls
…
Total: N boys and
1N 2N 3N 4N
– + – + – + — +… = ~N

Therefore the proportion of boys to girl will be quite close to 1:1.

November, Their calandar was 13 days behind ours.

The girl was born on 29 February, thus she put 250 stamps every four years.
In forty years, she put stamps only 10 times which makes the total of 2500 stamps.
Her sister was born on any other day and she took out 50 stamps from the box forty times which makes the total stamp she took out to be 2000.

Thus after forty years, the girl’s box had only 500 stamps.

13 8 its prime number and then number of letter in prime number

Suppose that everyone is standing at A corner and they have to reach the B corner

Let the housemaid and Dog go to corner B first and housemaid returns back to corner A.

Next, the housemaid and the first son go to B and she comes back along with the dog.

Now the father and the second son go to B and father comes back.

Mother and Father go to B and the mother comes back.

Housemaid and Dog go to B and the father comes back.

Father and mother goes to B and Mother returns back.

Mother and first daughter go towards B, Housemaid and Daughter returns back.

Housemaid and second Daughter go to B and Housemaid comes back.

Housemaid and Dog goes to B.

So, everyone has reached the other side of the river successfully.

You are also a primate and you are human thus you are the most intelligent.

If Alex and Ryan stand back to back, then they can make it possible.