A Primary 5 maths question put up on Facebook has gone viral, stirring a lot of debate and stumps adults.
So when is Cheryl’s birthday? Below is a step-by-step solution to this primary 5 maths question. Find out how Albert and Bernard derive at Cheryl's birthday.
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| The Primary 5 Question that have gone viral on facebook -- Photo: Kenneth Kong/Facebook |
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| Step 1: Eliminate May and June |
Reason: Albert know the month whereas Bernard know the day. Albert know Bernard doesn't know the birthday because the month is not May or June. If the month is May or June, there is a chance that Bernard will know the birthday if the day is 18 or 19.
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| Step 2: Eliminate 14 |
Step 2: Eliminate 14
Reason: Bernard know the birthday now. Remember Cheryl only told the day to Bernard. Why Bernard is able to know the birthday after eliminating May and June is the birthday day cannot be 14. If it is 14, then Bernard will have 2 choice and he will not know the birthday. So cancel both July 14 and Aug 14.
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| Step 3: Eliminate August |
Reason: After Bernard announce he know the birthday, Albert now also knows the birthday. Remember Cheryl told Albert the birthday month. If the month is August, Albert will not know the birthday as he will have 2 choice, Aug 15 or Aug 17. Since Albert know the birthday now. Then the birthday cannot be in August. So the only answer is July 16.
July 16 is Cheryl's Birthday!
