While many of you hate math, some of you must be aroused by its intricacies and the deep turns and dives you have to take to solve a tricky problem. Currently, a math problem for 14-year olds is breaking the internet and tearing lives apart because people are unable to solve it. Many of you must be aware of the problem and tried to scramble your brains out. But if you haven’t come across this impossible math problem yet, here it is.
Give it a try and solve this impossible math problem ;)
Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.
May 15 May 16 May 19
June 17 June 18
July 14 July 16
August 14 August 15 August 17
Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.
Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard does not know too.
Bernard: At first I don’t know when Cheryl’s birthday is, but I know now.
Albert: Then I also know when Cheryl’s birthday is.
So when is Cheryl’s birthday?
This question hit the internet earlier this week when a TV host in Singapore posted this impossible math problem question and it went viral. As you read this question, the problem looks impossible to solve with minimal hints. But when you make some assumption and use some logic, the problem starts looking a bit simple. This question was posed to 14-year-olds in Singapore and Asean Schools Math Olympiad (SAMSO).
Another viral story of similar confusion took over the internet about a month ago when a picture of the blue-black dress posted on Tumblr divided the whole world into two.
Here’s is the solution of this impossible math problem via genius minds of Singapore’s Study Room.
First we need to figure out if Albert knows the month or the day. If he knows the day, then there is no chance that Bernard knows the birthday, so it must be that Albert knows the month.
From the first statement, we know that Albert is sure that Bernard doesn’t know the birthday, so May and June should be ruled out (the day 19 only appears in May and the day 18 only appears in June). In other words, if Albert had May or June, then he cannot be sure that Bernard doesn’t know, since Bernard could have had 18 or 19.
Following that statement, Bernard knows that May and June are ruled out.
Then, Bernard is able to know which month it is. So it must be either July 16, August 15 and August 17 (not 14th as then he can’t know).
Since Albert subsequently can also be sure of the date, he must know it’s July. If it’s August, he can’t be sure as there is August 15 and 17.
So the answer is July 16.
Did you get this impossible math problem right? Did you understand the answer and are you smarter than a 14-year-old? Tell us in comments below.