Anita
Posted on Wednesday, 12 November, 2003 - 05:50 pm:
... Between them they have 11 heads and 52 legs.

How many people and how many octopuses are in the tank?

This is one of the questions in my maths homework about simultaneous equations. Now, I'm sure it's really obvious, but I just can't seem to find the right way to go about solving this problem. Some help please?

Thankyou!
-Anita (yr10)
Emma McCaughan
Posted on Wednesday, 12 November, 2003 - 06:00 pm:
Decide on letters to stand for people and octopuses.

Now write an expression for the total number of heads, and another expression for the total number of legs.

Does that help?
Anita
Posted on Wednesday, 12 November, 2003 - 06:08 pm:
Aha, I think I see where I've been going wrong. I was thinking it in terms of:

X people + Y octopuses = 11 heads


so i wrote down:

xp + yo = 11

but now i see it can be simply:
p + o = 11

d'oh! well thanks for your help, it kind of jogged my mind to think properly. :-)
David Loeffler
Posted on Wednesday, 12 November, 2003 - 06:11 pm:
Irrelevant comment: do octopuses actually have heads as such? If not it's a really easy problem, and you find that the number of octopuses isn't a whole number, so presumably you're supposed to assume they do, or else that there's some octopus-mutilation going on.
Emma McCaughan
Posted on Wednesday, 12 November, 2003 - 06:25 pm:
By the way, it's usually best to avoid using o as a variable - it gets confusing.

Don't octopuses have tentacles?
Matthew Aldridge
Posted on Thursday, 13 November, 2003 - 01:00 pm:
I thought it was octopi...
Marcos
Posted on Thursday, 13 November, 2003 - 01:08 pm:
I don't think so, because octopus is from Greek whereas things like radius (which does become radii) are from Latin.

Marcos
David Loeffler
Posted on Thursday, 13 November, 2003 - 03:06 pm:
According to Fowler's English Usage:
Quote: The only acceptable pl. in English is octopuses. The Greek original is oκτωπoυς, - πoδ- (which would lead to a pedantic English plural form octopodes). The plural form octopi, which is occasionally heard (mostly in jocular use) is misconceived.


David
Vicky Neale
Posted on Friday, 14 November, 2003 - 05:50 pm:
You might need to check that the octopuses haven't counted their own legs, or you'll find the answer is in base 8...

Vicky