Monday, 15 July 2019

Amazon Prime Days

They spent a lot of money advertising their Prime Days, which appear to be 15 and 16 July.

15 and 16 clearly aren't prime numbers, so that's a bad start.

If you write the date and month the English way, 157 and 167 are prime numbers (hooray, the world makes sense again) but if you write them the American way as 715 and 716 they are clearly not prime (bugger).

There are plenty of consecutive prime dates using the English format in January, March, July, September and November (apart from "2" and "5", all prime numbers end in 1,3,7 or 9).

But the only pairs of consecutive dates which are prime using the American format, are:
2/29 (in a leap year) - 3/1;
3/31 - 4/1.
12/31 - 1/1.

(You can't have consecutive primes in any calendar month using American format because one of them will be even, so you are restricted to the last day of a month with 29 or 31 days, followed by the first day of next month.)

I couldn't find any consecutive dates which are both prime using English format and American format.

Just sayin'.


James Higham said...

You're not an accountant by any chance, are you? :)

Mark Wadsworth said...

JH, I'm a failed maths professor who settled for accountancy.

Mark In Mayenne said...

The world needs nerds

JuliaM said...

I didn't even understand the first paragraph!

Mark Wadsworth said...

MiM, the world gets nerds whether it needs them or not.

JM, that was the easiest paragraph.