by Hugh Bradley and Christopher Higgens
Bobby has made a Valentine card for his girlfriend Chin-We. He drew rows of identical touching circles in a triangular formation as shown on the left but with more rows.
He then placed a red heart in as many circles as possible without any of these forming equilateral triangles. He continued by placing pink hearts in some of the other circles and white hearts in the remainder. When he counted the number of hearts of different colours (in no particular order) he obtained three consecutive numbers.
How many red hearts are on the card?
One from the past, this one with a sting in its tail!