articles such as this one usually are optimized for their audience, you just aren't the audience. that's ok. I'm rarely the audience either :)
a quick search should give you what you're looking for https://www.science.org/doi/10.1126/sciadv.adz3040
It was pointed out that the first price was higher originally. The funny thing is that in that case the price of four would be nice to know. With the given information it would be economically more efficient to buy two times two if you wanted four vs one times three and then an additional one.
"one of my girlfriends" casual flex.