Settle a debate. Every 3 days?

[WrendaleCountryDogs]

You need to do something "every 3 days"
You first to it on Tuesday at 9am. Is the next time on Friday or Saturday?
I think Friday, my mum thinks Saturday.

Friday

Friday

My first thought was Friday

But now I am thinking is your mum on to something?

Every 3rd day, so Friday.

Day 1 - Wed
Day 2 - Thur
Day 3 - Fri

Friday

Friday

Friday.

If you did it every seven days you would do it again next Tuesday, not Wednesday.

Friday

Instead of saying “every 3 days” think of it as “every 72 hours”. From 9am on Tuesday, after 72 hours have elapsed it’s 9am on Friday.

Yes, I was thinking 72 hours.

Another one for Friday

I was doubting myself so thought of it like this....
If you do it Tuesday, then every (1) day is Wednesday, every 2 days its Thursday, every 3 days is Friday.

Not sure how your mum gets Saturday unless she's thinking leave 3 day gap - but that's 4 days later.

I do it every 2 days but only a little bit on Sunday mornings. Your mother needs better advice. 😗

Friday

Friday.

Friday