h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I recently went on holiday to stay with my counsin Vinny T. Cat. We had a brilliant time together! In the mornings, we both would go for a jog. The evenings were spent on the tennis court. Tiring as these activities were, we could manage only one per day, i.e., either we went for a jog or played tennis each day. There were days when we felt lazy and stayed home all day long, me eating doughnuts, he drooling as he watched me.

Now, there were 15 mornings when we did nothing, 11 evenings when we stayed at home, and a total of 12 days when we jogged or played tennis. For how many days did I stay at my cousin Vinny's place?

19

16

What's this the battle of the Irish or are the Irish the only one's up at this time on a Friday?

Nope, the expats are here as well, they just haven't woken up yet

Congratulations Gnomon... now will someone please put a pot of coffee on

23

And I missed it because I was still discussing my UCAS form with the deputy head of 6th form... *sigh* Otherwise I could have been online for that one too, and got it horribly wrong as well...

¦M¦

12 days doing activities fine 11 evenings off and 15 mornings off means 4 days off total inactivity

12+4 does not equal 16 so don't praise Gnomon too early me thinks.

No you're not.

I'm guesing 23.

Geggs

23

CORRECTION

12 days doing activities fine 11 evenings off and 15 mornings off means 4 days off total inactivity

12+4 does not equal 19 so don't praise Gnomon too early me thinks.

My reasoning was: 12 mornings or evenings with activity, 26 mornings and evenings with no activity. Total number of mornings and evenings 38. Total number of days 19.

I was thinking like this (probably wrong, but anyway):

15 days doing nothing in the morning
Of those 15 days 11 doing nothing in the evening as well
Which gives 11 days of no activity at all
Adding 12 days of some kind of activity, whether it was in the morning or the evening
11 + 12 = 23

Slightly different method of calculation, but same result as Gnomon

15 mornings rest + 4 mornings of sport
11 evenings rest + 8 evenings of sport

= 19 full days, with 12 days of sport

I've changed my mind. It's 19.

Found by the rather boring method of working it out on paper.


Gnomon wins.


Geggs

My biggest problem in that was dividing 38 by 2.

My reasoning appears to be off I now concur that the answer is my lucky number.

My idea involved using a spreadsheet. (Not sure if this is cheating, but I've never been able to get here first anyway.)

Shade 15 blocks down for mornings, and 11 blocks down next to them for the evenings, then move the 11 blocks down until you have 12 days of activity. The days of inactivity will be where the shaded areas still overlap. The total days will be where the 11 blocks end. It comes out at 19.

Maybe not the smartest solution, but it worked.

Ah! *Now* I finally get it - being a bit (more than a bit, rather) daft today...