'Primary 5' maths question turns out to be Sec 3 Math Olympiad question. The correct official answer is 16 July. Here is the explanation from Strait Times website.
A Primary 5 math question went viral recently and become a subject of intense debate. We think we have the answer, and it is 17 August. Here goes our reasoning.
The premise is as follow:
Albert knows the Month of the birthdate
Bernard knows the Date of the birthdate
Here is all possible dates of the birthday mapped out in tabular form, for ease of viewing. Possible dates are marked in blue.
Now we know that Bernard knows date of the birthdate, therefore 18th and 19th are not possible, because if it is correct, Bernard would have known the answer.
Albert knows that Bernard does not have the answer, and Albert could not guess it as well. That means that 17th June is impossible, because if the correct month is June, 17th is the only date option left. and Albert will know the answer.
After knowing that Albert did not have the answer, Bernard now knows the answer. That is only possible if the correct date is 17th. Since 17th June is out, the only possible answer is 17th August.
There you go, the answer is 17th August. Drop us a comment if you think you have a different answer. On a side note, Fynd provides on the spot iPhone Repair at your doorstep, as well as computer repair and data recovey. Drop us a line if you need our help.