9 replies to this topic

[Anza Power]

Try to answer this one as quickly as possible:

Your friend tells you: "Each year my birthday comes in the same day of the week as my younger brother's because they're exactly 14 days apart, I was born on a Monday so that means he was born on a Monday too"

Is she correct?

[curr3nt]

Spoiler for well...

maybe.
She is correct if the younger sibling was born in a year that her birthday occurred on a Monday.

If the younger brother is only say two years younger then she is incorrect because her birthday would be a different day of the week for that year.

[mrzinks]

Spoiler for If...

If 'each' means 'every', then she is correct.

[bonanova]

Try to answer this one as quickly as possible:

Your friend tells you: "Each year my birthday comes in the same day of the week as my younger brother's because they're exactly 14 days apart, I was born on a Monday so that means he was born on a Monday too"

Is she correct?

Spoiler for Looks like

No.

Suppose your birthday is December 20, and your brother's follows by 20 days on January 3.

In 2012, you celebrate Thursday, while your brother already celebrated, on Tuesday.

In twenty days your bro will celebrate on Thursday, of course. But it will be 2013.

Good puzzle. I didn't reply very quickly.

[curr3nt]

I think the spoiler ate bonanova's answer.

[Rob_Gandy]

Spoiler for I agree with curr3nt

If they are 5, 6 or 11 years apart (or some sum following the pattern +6, +11, +6, +5 or some variation that keeps the same order) then maybe if the years are right, but any thing else no.

[nakulendu]

Spoiler for close siblings

she is not correct if their birthdays are between 14th Feb and 13th march. In leap years their birthdays will not be on the same day in this case. Otherwise if their birthdays are apart by 14 days apart, they would always be on the same day of the week

Edited by nakulendu, 11 October 2012 - 07:47 AM.

[TheChad08]

Spoiler for close siblings

she is not correct if their birthdays are between 14th Feb and 13th march. In leap years their birthdays will not be on the same day in this case. Otherwise if their birthdays are apart by 14 days apart, they would always be on the same day of the week

Spoiler for

She was BORN on a Monday. She isn't saying that her birthday is on a Monday. If I was born on Oct 11 2011 I'd be born on a Tuesday. If my younger sibling was born on the same date (equivalent to 14 days later) but a year later (Oct 11, 2012) they'd be born on a Thursday. 365 doesn't equally divide by 7 so the days of the week and the specific dates don't always match up.

Edited by TheChad08, 11 October 2012 - 03:26 PM.

[Prof. Templeton]

Spoiler for Additional

difficulties can also be found in certain years (ie. 1582,1587,1700,1752,1753 and 1918). There may be others. Agree though, good puzzle.

[~andy~]

No, she's only correct if the brother was born in a year that her birthday was on a Monday

So the answer is NO