Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**khushro****Member**- Registered: 2015-04-10
- Posts: 2

The solution was very disappointing. It was just a straight-forward counting of the number of objects, which even an idiot with a calculator can do. There was nothing puzzling about it.

I was expecting a more mathematical solution, which would give the correct answer for n days instead of 12, and then substitute n=12 in the answer. Would not remain a starter, but would at least be a puzzle.

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 4,592

Hi khushro,

Yes, the given solution method is rather starter-ish.

A more satisfying solution exists, however, which by way of a nice mathematical formula in terms of *n* eliminates all that counting and will instantly display the answer for *n* (eg, *n*=12) days.

The formula can be found on the net, but, if you'd like to have a go at constructing it yourself, then here are a couple of hints (should you need them):

*Last edited by phrontister (2015-05-20 13:58:17)*

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Offline

**Laatokka****Member**- Registered: 2016-06-07
- Posts: 1

Hi,

And if you want, you can try making a little program and modify it

(JavaScript)

var x = 1;

var y = 2;

var days = 1;

var PresentsPerDay = 0;

while (days < 13){

PresentsPerDay=x+PresentsPerDay;

x=x+y;

y++;

days++;

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 4,592

True!

A similar program in BASIC:

```
x=1
y=2
d=1
ppd=0
WHILE d<13
ppd=ppd+x
x=x+y
y=y+1
d=d+1
WEND
PRINT ppd
```

And...welcome to the forum!

*Last edited by phrontister (2016-06-07 23:10:17)*

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Offline