Sometimes a very trivial thing gets you into never-ending agony of an incomprehensible mystery.

It happened to me on a beautiful Sunday afternoon of a beautiful summer day. I was making my favourite type of coffee poured into my favourite mug, listening to my favourite radio station. Then I opened a packet of my favourite biscuits: Tim Tam.

The sweet-smell of chocolate hit my nose. (My favourite Tim Tam flavour is the Original.) It was pure happiness. I sat on a couch, then sipped a mouthful of aromatic coffee and enjoyed a blissful bite of a Tim Tam. And then another bite, and another.

And then, as a responsible adult, I told myself that I should save the rest of Tim Tams for “tomorrow”.

Out of genuine curiosity, I wondered how many biscuits a pack of Tim Tam contains. I checked the package. And I was utterly dumbfounded.

‘Eleven biscuits’, it read.

Eleven. Why eleven?! Eleven is a prime number. You cannot equally share 11 biscuits with other people. One short from 12 seemed to be complete nonsense or mistake of some sort. I tried to remember all the marketing theory I have learned but couldn’t find any justification for such a package.

I immediately googled “why Tim Tam has 11 biscuits”. But I couldn’t find any convincing answer. All I could find was someone’s complaint about some special flavour Tim Tam which came with 9 biscuits. So there were variations. But it didn’t help my puzzlement about the prime number.

I tried to think of the fairest allocation of Tim Tams in various types of households.

Couples: 6 + 5 = They have to fight over the last one piece.

Couples with one kid: 4 + 4 + 3: This one seems the most reasonable variation: Each parent gets 4 pieces, and the poor kid gets 3.

Couples with two kids: 3 + 3 + 3 + 2: One of them would feel it is unfair.

Couples with three kids: 2 + 2 + 2 + 2 + 3: This one would lead to a lot of fighting. For this household, I recommend buying two packs, so that they will get 22 pieces (5 + 5 + 4 + 4 + 4).

Single parent with one kid: 5 + 6 = Not a problem. The kid will be happy.

Single parent with two kids: 3 + 4 + 4 = Not a problem. Kids will be happy.

Single parent with three kids: 2 + 3 + 3 + 3 = Not a problem. Kids will be happy.

I came to realise the eleven Tim Tam pack must have been designed to support single-parent households. It does make some sense if you think that to be the case. Or is it some kind of conspiracy?

Putting one of the “tomorrow”‘s Tim Tams in my mouth, I concluded that the best strategy is to buy two packs at a time to avoid a conflict in a household, even if you are living by yourself.