Can you answer this question for 14-year-olds from the Singapore and Asian Schools Math Olympiad?

20:03 cherishe 0 Comments

You’re gonna need a heavy dose of logic and probably a couple headache pills to tackle this one.

Being stumped by questions intended for children is something we’re used to here at SoraNews24, but oftentimes those kinds of questions are either things you see right away or you just feel stupid for not noticing earlier when someone tells you.

How about a question instead that’s nothing but cold, hard logic?

Recently, Japanese Twitter user @fmathsecond posted the English and Japanese versions of a question from the Singapore and Asian Schools Math Olympiad, which got a lot of attention due to its seemingly impossible premise. Here’s the original tweet: (Click the left image or scroll down to see the puzzle)

▼ “This was in the Singapore and Asian Schools Math Olympiad
for 14 to 15-year-olds and is well-known for being a hard logic puzzle.”

【シェリルの誕生日】シンガポール＆アジア数学オリンピックで14,15才向けに出題された問題論理的思考力が問われる難問として有名 https://t.co/2eiGu3oZq6
—
ラジオ2 (@fmathsecond) May 27, 2017

For those who can’t see the image, here’s the puzzle in MS-Paint form:

Yikes! Aside from Albert and Bernard needing to probably take a hint and get as far away from this psychopathic Cheryl person as fast as possible, the first thing that hits you is just how impossible the question seems right off the bat. We didn’t get any hints for dates or anything, so how can we possibly figure it out?

We won’t spoil the answer yet, but go ahead and take a few more read-throughs to see if you can figure it out. If not, scroll down for some hints, or all the way down for the answer. (And no, the awkward grammar in some places isn’t a clue or anything.)

▼ Hint #1: Just in case it wasn’t clear, Albert knows the month,
and Bernard knows the day. (Three hints remaining.)

▼ Hint #2: What number days could Bernard have been told by Cheryl that
would’ve let him know her birthday right off the bat? (Two hints remaining.)

▼ Hint #3: Albert isn’t just saying this underlined part for no reason. What
months could he know that would let him say this? (One BIG hint remaining.)

▼ Hint #4: Take a deep breath before this one.

In answer to Hint #2, the only unique number days on the list are (June) 18 and (May) 19, so the number Bernard was told could not have been 18 or 19. Otherwise he would’ve been able to spot the birthday right away.

In answer to Hint #3, because May and June have those unique number dates (18 and 19), for Albert to know that “Bernard does not know,” he must have been told that the date was in July or August. Otherwise there would be the possibility that Bernard could know the birthday from the number day alone, and with the double appearance of numbers 14, 15, 16, and 17, Albert can definitively say that “Bernard does not know too.”

This lets us cross out all the dates in May and June, leaving only the dates in July and August. Can you solve it from here?

(Scroll down for the answer.)

▼ Answer: Since Bernard says he now knows the birthday,
we can eliminate the two dates that share the same number day…

▼ …and since Albert says he now knows the birthday, we can eliminate the
two dates that share the same month, leaving us with the answer: July 16!

Phew! Did you figure it out? It took me a while. That first logical leap of crossing out May and June takes quite a lot of mental sweat, but after that it’s not too bad.

Here’s how Japanese netizens responded to Cheryl and her insane birthday torture:

“I have no idea what any of this means.”
“Please… someone… help me….”
“Hey! I got it! But… wow. That took a while.”
“I’ve known a woman or two like Cheryl in my lifetime.”
“Wow, I feel like my brain just lifted some weights. More please!”

Fear not, netizen, we have your back! Try this math question that Japanese Twitter claims only those with an IQ of 150 or higher can solve.