51 replies to this topic

[rookie1ja]

The Elder Twin - Back to the River Crossing Puzzles
One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How come?
This puzzle was submitted to Games Magazine's 'How Come' competition in 1992 by Judy Dean. It won.

This old topic is locked since it was answered many times. You can check solution in the Spoiler below.
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Spoiler for Solution

The Elder Twin - solution
At the time she went into labor, the mother of the twins was travelling by boat. The older twin, Terry, was born first early on March 1st. The boat then crossed the International Date line (or any time zone line) and Kerry, the younger twin, was born on February the 28th. In a leap year the younger twin celebrates her birthday two days before her older brother.
This puzzle was submitted to Games Magazine's 'How Come' competition in 1992 by Judy Dean. It won.

[puzzlewuzzle]

Actually there is another solution. There was a rare case in America where a mother became pregnant some 6 months after she had already concieved. Since both children were in the womb together they are classed as twins though there birthdays were months apart. As far as I know both children were completely healthy

[rookie1ja]

Actually there is another solution. There was a rare case in America where a mother became pregnant some 6 months after she had already concieved. Since both children were in the womb together they are classed as twins though there birthdays were months apart. As far as I know both children were completely healthy

That's interesting. However, it does not fit the puzzle since the twins can not celebrate their birthdays months apart. As written in the puzzle:

Two days later her older twin brother, Terry, celebrated his birthday.

[rayne1984]

One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How come?


Actually there is yet another possible answer. It could be the case that Kerry has a set of older twin siblings and the question only refers to one of them, Terry while the other (Jerry?) is not mentioned for the sake of ambiguity.

[rookie1ja]

If there were more than 2, wouldn't they be called triplets?

[puzzlewuzzle]

Not if she wasn't one of them.
Imagine it is so:
Kerry is 10 her birthday is on the 12th of March.
She has two brothers, who are twins, one of them, Jerry is the older as he was born at 23:50 and the other Terry was born at 00:10 the next day, they are both 13. Jerry therefore celebrates his birthday on the 14th of March while Terry celebrates his on the 15th.
The situation would hold true that Kerry celebrated her birthday one day, and her older brother, who is a twin, celebrated his two days later. It does not specify that Kerry is a twin only that her older brother is.

Complicated but it could work...
Parents anniversary is probably 9 months before the 12th of March, work that out..!

[qazqaz]

One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How come?

i dont celebrate my birthday on the exact date of my birth, could the same be true fot them?

[puzzlewuzzle]

No

[maggie0308]

The solution could work this way also: Mom gives birth to one twin on the evening of February 28th, and the other arrives shortly after midnight March 1st... So, then on leap year, the birthdays are two days apart.
No traveling through time zones for Mom! What Mom in her right mind would be traveling *and* laboring!
Same result with much less effort!

[rookie1ja]

The solution could work this way also: Mom gives birth to one twin on the evening of February 28th, and the other arrives shortly after midnight March 1st... So, then on leap year, the birthdays are two days apart.
No traveling through time zones for Mom! What Mom in her right mind would be traveling *and* laboring!
Same result with much less effort!

But then it would not fit the following:

Two days later her older twin brother, Terry, celebrated his birthday.

The older twin would celebrate before the younger one.