I knew I shouldn't have posted a quick answer while getting ready for work...
Quote:
Originally Posted by Allan_L
Hey Sheeny
What about 1x17?
(a rectangle 1 metre by 17 metres is not a straight line).
[the straight line only comes into contention where "units" equals pixels]
And a Square is ALWAYS a rectangle. Opposite sides equal and all angles 90 degrees. (I doubled checked definitions before going into print on this one)
So the formula is n/4 (and ... always rounded DOWN)
and I don't understand Q1 at all ???
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Absolutely correct on the rectangles!
Well, now that I've read it some more, there are some rules missing to make the question unambiguous.
I assumed that the digits sharing the columns would be added together... we all know about ASSuME! The question doesn't say whether they are added, multiplied, or whether normal place column rules apply.
Quote:
Originally Posted by wasyoungonce
Permutations. If you had a 4 digit number and wrote that number into 4 blank boxes (one at a time, reducing the selections left by not re-using the same digit) how many way can it be written.
ie the number is 2134. We can write combinations or permutations of this as:
Any of the 4 digits x any of the 3 digits left x any of the 2 digits left x any of the 1 digit left = 4 x 3 x 2 x 1 = 24 ways of writing it.
It really doesn't matter what the digits are they could be any as the number of ways of writing permutations of it is the same.
In maths it's written 4!
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I don't believe the question is about permutations or combinations. they are clearly refering to place columns i.e. the RH column is units, the 2nd from the right is tens, etc. The question is what real numbers are possible if you are allowed to have more than one digit in each place column. I assumed the digits in each place column would be added together (e.g. 1 & 3 in column 2 = (1+3)x10 = 40). But since this problem is playing with some fundamental maths rules, the behaviour you are expected to use for these digits needs to be spelled out to make it unambiguous. For example, the 1 & 3 in column 2 could be interpreted as 13, hence 13 x 10 = 130)
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Quote:
Originally Posted by MrB
I got tricked at first too, the question asked for 9L
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Oh yeah...
... what did my old school teachers always tell us??? Read the question!
Al.