Brain Teasers
Five Cousins
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Five cousins are celebrating New Year's Day. Using the following clues, determine each person's age, birth date, and birth time.
Names: Alvin, Donna, Jerry, Laura, Steve (Donna and Laura are girls)
Ages: 28, 29, 30, 31, 32
Months: February, May, June, August, October
Dates: 9th, 11th, 15th, 29th, 31st
Times: 6:00 AM, 9:00 AM, 2:00 PM, 5:00 PM, 7:00 PM
1) Two of the boys were born in a leap year.
2) Neither girl was born in the morning.
3) Both girls were born in the first half of the month.
4) One of the boys was born three hours later in the day than one of the girls.
5) No one celebrated a golden birthday last year, and no one will celebrate a golden birthday this year.
6) The five people are: Alvin, the person who is 32 years old, the person born in August, the person born on the 11th, and the person born at 9:00 AM.
7) The person born at 6:00 AM is older than the girl born on the 15th, who is older than the boy born in October.
8) Jerry was born earlier in the year than the person born on the 11th, who was born earlier in the year than the person who is 28 years old.
9) The person born in May was born earlier in the month than the person born at 7:00 PM, who was born earlier in the month than the person who is 30 years old.
10) The person born on the 29th was born earlier in the day than the person who is 31 years old, who was born earlier in the day than the person born in June.
11) Steve and Donna have the two closest birthdays.
Names: Alvin, Donna, Jerry, Laura, Steve (Donna and Laura are girls)
Ages: 28, 29, 30, 31, 32
Months: February, May, June, August, October
Dates: 9th, 11th, 15th, 29th, 31st
Times: 6:00 AM, 9:00 AM, 2:00 PM, 5:00 PM, 7:00 PM
1) Two of the boys were born in a leap year.
2) Neither girl was born in the morning.
3) Both girls were born in the first half of the month.
4) One of the boys was born three hours later in the day than one of the girls.
5) No one celebrated a golden birthday last year, and no one will celebrate a golden birthday this year.
6) The five people are: Alvin, the person who is 32 years old, the person born in August, the person born on the 11th, and the person born at 9:00 AM.
7) The person born at 6:00 AM is older than the girl born on the 15th, who is older than the boy born in October.
8) Jerry was born earlier in the year than the person born on the 11th, who was born earlier in the year than the person who is 28 years old.
9) The person born in May was born earlier in the month than the person born at 7:00 PM, who was born earlier in the month than the person who is 30 years old.
10) The person born on the 29th was born earlier in the day than the person who is 31 years old, who was born earlier in the day than the person born in June.
11) Steve and Donna have the two closest birthdays.
Hint
Some helpful steps (though not all) are listed below.1) February and June do not have 31 days, so neither month can have 31 days. February can only have the 29th in a leap year.
2) A golden birthday is when a person becomes the age that is the same as the day of birth. For example, a person born on the 10th of a month celebrates a golden birthday when that person turns ten years old. Since a golden birthday was not celebrated last year and will not be celebrated this year, the persons who are 28 and 29 were not born on the 29th, and the persons who are 30 and 31 were not born on the 31st.
3) For two boys to be born during leap years, they must be four years apart in age. Therefore, one boy must be 32 years old, and another boy must be 28 years old.
4) One boy was born three hours later in the day than a girl. There are only two situations that satisfy that requirement: a girl born at 6:00 AM and a boy born at 9:00 AM, or a girl born at 2:00 PM and a boy born at 5:00 PM. Since no girl was born in the morning, then that leaves a girl born at 2:00 PM with a boy born at 5:00 PM. That also means that the other girl was born at 7:00 PM.
5) Since one of the girls must be born on the 15th, and both girls were born in the first half of a month, the 15th can not be in February.
6) With the remaining combinations of months and days, the two closest birthdays can only be in May and June.
7) Since it has now been established that the 29th is in February, then it must be matched with a person born in a leap year, which can only be the person who is 28 or 32. It has been established that the person who is 28 was born on October 31st, so the person who is 32 was born on February 29th.
Answer
Alvin, 28 years old, born on October 31st at 5:00 PMDonna, 29 years old, born on June 11th at 7:00 PM
Jerry, 32 years old, born on February 29th at 6:00 AM
Laura, 30 years old, born on August 15th at 2:00 PM
Steve, 31 years old, born on May 9th at 9:00 AM
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Comments
Very well constructed. It was a challenge but workable. Great job!!
It was a workout for my feeble brain, but I loved it!
Steve and Donna have the two closest birthdays only if you ignore the year. If you take the year into account, it is Alvin and Donna.
that was hard. my brain hurts now.LOL
Wow, that was difficult. I have no idea how many times I tried to solve it, but I eventually did. Still not to sure how I did it. Nice job!
thats teaser really made me think...cool teaser though
GREAT work. Thanks!
A nice challenge -- had to restart a couple of times, due to some carelessness in filling in the grid.
But where does the "golden birthday" thing come from? I'm 62 years old and had never heard the term -- had to google to find out what it meant. Is this some invention of the gold cartel to sell more gold jewelry?
But where does the "golden birthday" thing come from? I'm 62 years old and had never heard the term -- had to google to find out what it meant. Is this some invention of the gold cartel to sell more gold jewelry?
cnmne, another excellent puzzle! I had to sleep on this one to fill in those last squares the next morning. Great concept with the leap year scenario - made my brain work a little harder to incorporate that.
I concur with chriscat's commnet about the "golden birthday" definition. I had never heard of it either and had to look it up. (If you're able to edit the puzzle, please include the definition in the main challenge clues.)
I concur with chriscat's commnet about the "golden birthday" definition. I had never heard of it either and had to look it up. (If you're able to edit the puzzle, please include the definition in the main challenge clues.)
Addressing cunningrat's comments about the birthday's near each other: I'll often hear people express, "Oh, we have the same birthday" when they are obviously different ages.
Enjoyed this one!
It was a big pain
I had to "check" the answers,
I had to "check" the answers,
good puzzle, thank you. I really enjoyed the leap year element.
That. Was HARD. I had to restart several times, and I usually get these on my first try, even the hard ones (I program as a hobby, am on my school's math team, excel in a game called go, and can solve these puzzles faster than anyone I know). So kudos to you!
Whewwww. That was tough. Basically it all boils down to gender determination.
Thanks for the puzzle!
Thanks for the puzzle!
Great LG! Really tough but keeps me thinking. The only problem I have is that I can't see where you figure that the 29th is in Feb (see hints). Just because someone is born in a leap year, does not mean they were necessarily born on Leap Day and nowhere in the clues does it state that.
Agreed with dreamlvr1432, great puzzle but the jump to 29th February seemed like a giant leap in logic! (pardon the pun). Would have loved a more detailed explanation on point 6 as well.
Oops - also this point:
It has been established that the person who is 28 was born on October 31st
It has been established that the person who is 28 was born on October 31st
Hint says the following: "Since a golden birthday was not celebrated last year and will not be celebrated this year, the persons who are 28 and 29 were not born on the 29th"
However, the person who is 28 would have been turning 27 last year and 28 this year, so they could still have a birthday on the 29th. The hint is wrong. I think this puzzle is difficult because there's not enough information to fully solve without making some guesses and checking.
However, the person who is 28 would have been turning 27 last year and 28 this year, so they could still have a birthday on the 29th. The hint is wrong. I think this puzzle is difficult because there's not enough information to fully solve without making some guesses and checking.
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