Thread by @JimmerUK

I've got a lot of work on, so naturally I ignore it all and do something silly instead.
Here is the Mcdonald's Fries Theorum. 🧵

When ordering McDonald's, my wife asked for medium fries rather than large "Because there's not actually any more chips in them, it's a con!" So I decided to test it.
FALSE: There are more fries in a large. Job done.
But, the large fries are in a larger box...

So I zero out the scales with a bowl and weigh the chips.
FALSE: There are more fries in a large. Job done.
18g more, to be precise...

Which interestingly (excuse my fast and loose usage of 'interestingly') means that the large has 2g of extra cardboard.
Here's what 18g of fries looks like.
But...

A large has 116% of the fries of a medium, but, at £2.29 vs £1.79, is 128% of the price.
Surely, then, there is a point where it's cheaper to buy more medium portions than large portions.
Turns out, there is. And it's not as many as you might think...

I wanted to find the crossover point where buying just one more portion of medium fries made it more cost-effective than buying large fries. And here are the results.
See it?

If you buy five portions of medium fries, it's cheaper than four portions of large fries by 21p and you get 37g more fries!

This works up to 7 mediums vs 6 large where you get 1 gram extra of fries for £1.21 less! After that, it gets cheaper but you do get fewer fries.

So there you have it. I suspect there is much more important maths yet to be done, but it will have to be by smarter people.
If you also have an inquiring mind, do some tests yourself and report back with your results.
Now, back to work.