Brain Challenge or Brain Challenge:
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Radha is the new child of Ramu and Raju. One day, they both asked Radha for her birthday. After consulting one, Radha said, I'm not going to say, but give you a clue. Radha then handed them a list of 10 dates and said, "My birthday is one of these dates".
July 13th, July 17th
May 16, May 17, and May 20
June 18 and June 19
Aug. 13, Aug. 16, Aug. 18
Then she told Ramu's ear only the month of her birthday. Likewise, Raju's ears were told only on the day of birth. Then he asked Ramu "Did you get the grip?"
Ramu: "I don't know, but I'm sure Raju doesn't know either."
Raju: "I didn't know until Ramu said this, but now I know."
Ramu: "Now I got it"
Q: What date is Radha's birthday given above?
PS: 1. This is not a cunning question. It is a clear-cut question that needs to be solved logically. If someone answers their own brain talk, let's discuss.
Any one can answer the Q .. ???
Answers
Radha's birthday is on July 17th.
This can be solved as follows( by eliminating the incorrect options):
1. Ramu knows the month whereas Raju knows the date.
Now when Ramu says that he doesn't know and also is sure that Raju isn't aware of the correct date, it means that it is not on an unique date, i.e. 19th and 20th.
Therefore, we eradicate the possibility of her birthday being in May and June.
2. Now considering July, we see that if the date is 17th, then it matches all the statements of Ramu and Raju.
Firstly, since July has two dates, Ramu says that he doesn't know and also sure that Raju doesn't know. From here, Raju gets to know that it must be either July/August and it must be 17th as it is an unique date between July and August.
July 17
Step-by-step explanation:
The given dates are:
July 13th, July 17th
May 16, May 17, and May 20
June 18 and June 19
Aug. 13, Aug. 16, Aug. 18
Ramu knows the month and Raju knows the date.
Ramu says he doesn't know and that Raju shouldn't know either. This eliminates the dates that is not unique. 19 and 20 are unique. May and June contain these two dates. So the whole list of May and June dates can be eliminated.
We are not left with July and August dates, 5 items.
Now, we must pick the unique date between these months, which eliminates 13. August is left with two dates, 16 and 18, so they are not unique either.
So we are left with July 17 which is her birthday.