Zorac (zorac) wrote,
Zorac
zorac

Number Puzzles

Somethin' to exercise your li'l (sorry) grey cells, a couple of numerical puzzles. First person to solve them both wins 15 seconds of fame.

If A and B can fill a tank in 4 hours, A and C can fill the tank in 5 hours, and B fills twice as fast as C, how long does it take for C to fill the tank alone?
Fairly straightforward, but either the Invariants being slow, or we were all being polite and letting other people have a chance to figure it out...

So, I'm broswing around Sainsbury's, when I see they have large packs of Strongbow (18x440ml cans, normaly £14.99) reduced to half price. Seems like a good offer, but they also have 4-packs at £3.59 each with 500 nectar points if you buy two packs. In addition, these cans have x% extra free, making them a full pint. Question is, which of these offers is better value for money?
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That pretty much tallies with my mental arithmetic chez Sainsbury. £2.88 is the magic figure for what you need to make your voucher worth, and as a McD's extra value meal now costs more than that, you're sorted.

Of course, another angle of attack is to ignore the extra free on the grounds that is the number of drinks that counts plus you get the bonus of slightly reduced hangovers. In this case you need to get over £5 per voucher, which is pushing your luck some.

The real danger with this sort of scheme is that you count your money twice, eg:
1) I've earned 500 points which is like saving £2.50!
2) I've used a 500 point voucher to save me another £2.50!
A gallon of cider and a McD's extra value meal?

This is your private health insurance company speaking. Your premiums have just nontupled.

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    I mentioned a couple of weeks back that I was playing The Longest Journey - an entry of that oft-neglected genre of computer games, the…

  • Random media ramblings...

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