How can I work out what day of the week it'll be after x amount of days?

Some kind of formula to this......

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- Jan 16th 2010, 06:26 AMethioWhat day will it be after a 100 days
How can I work out what day of the week it'll be after x amount of days?

Some kind of formula to this...... - Jan 16th 2010, 06:45 AMawkward
- Jan 16th 2010, 07:40 AMethio
Sorry for this but can you give me an example? say...any number of days from today, with a full workout.

- Jan 16th 2010, 09:36 AMPlato
As was suggested number the days. $\displaystyle \boxed{\begin{array}{lllllll} {Su} & M & T & W & {Tr} & F & S \\\hline 0 & 1 & 2 & 3 & 4 & 5 & 6 \\ \end{array} }$

If we divide 25 by 7 we get a remainder of 4.

If today is Sunday then in 25 days it will be Thursday: 0+4=4. Four is Thursday.

But if today is Friday in 25 days it will Tuesday: 5+4 divided by 7 has a remainder of 2 and 2 is Tuesday.

So divide x by 7 to get a remainder. Add that to the number of the day and then find the remainder when divided by 7 that number day in x days later. - Jan 16th 2010, 01:13 PMethio
Thank you both.