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Life & fun · April 15, 2015

IW

I wrote an explorer for the Singapore Olympiad problem

I wrote an explorer for the Singapore Olympiad problem launched on April 15, 2015 with 11 votes, #1,161 of 3,600 launches that month and more than 75% of that year's launches. The site was still online in September 2026, 11 years on.

Visit mark.github.io ↗Alternatives

In plain words

This interactive tool helps users explore the Singapore Mathematical Olympiad's viral birthday logic puzzle. It allows visitors to select potential dates for Cheryl's birthday and then trace through the logical deductions made by two puzzle-solvers named Albert and Bernard. The site highlights contradictions in red, showing which claims don't align with the selected date and explaining why. It's designed for anyone wanting to understand how to work through this popular lateral thinking problem step by step.

written from the facts on this page · September 2026

From the sources

A problem from the Singapore Mathematical Olympiad has been travelling around the internet, since being shared on Facebook by Kenneth Kong . This site provides an easy way to work through the problem, to better understand the correct solution and how to solve the problem. Click on one of the possible dates for Cheryl's birthday. Then you can follow the thoughts that Albert and Bernard have as they attempt to solve the problem. If one of the claims they make does not match up with the date you selected, then that claim will show up in red , and you can hover over it to see why it is incorrect. If Bernard heard 14, then he thinks it is July 14th or August 14th. If Bernard heard 15, then he…from mark.github.io

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