conundrum time...

[scfcrmagic]

A zookeeper has lost the ability to distinguish between elephants and emus...However, he is able to count eyes and feet.
He counts 58 eyes and 84 feet.

How many elephants and how many emus are there??

[StokieMatt]

ask them jump

[londonjamie]

It doesn't matter because he is being humped by a lion.

[scfcrmagic]

Roy Walker stylee ......thats good but its not right ... ;D ;D ;D

[Andrew]

no idea.

[Beardy200]

16 Emus
13 Elephants

[scfcrmagic]

Mar 5, 2010 20:43:16 GMT Beardy200 said:

16 Emus
13 Elephants

Thanks Beardy .....knew you'd know the answer ...
you are right clever .....

[isaaccox]

or you type it into google and it tells you, now thats clever.

[scfcrmagic]

Beardy would have worked it out ...he's a genius ...Fact !!

[scfcmacca]

Mar 5, 2010 20:43:16 GMT Beardy200 said:

16 Emus
13 Elephants

what he said

[addistokie]

i knew that all along!

[Malex]

I can't believe I am about to do this at 3am on a Saturday..

let x1 be emu's and x2 be elephants. Both have 2 eyes, Emus have 2 legs, Elephants have 4 legs, so..

(1) 2 x1 + 2 x2 = 58
(2) 2 x1 + 4 x2 = 84

Solving for x2, subtracting (1) from (2) gives:

2 x2 = 26, dividing by 2 gives: x2 = 13

Put that back into either of the equations...

(1) 2 x1 + 2 x2 = 58 ... 2 x1 + 2(13) = 58 ... 2 x1 + 26 = 58

(-26) 2 x1 = 32

(/2) x1 = 16

OR

(2) 2 x1 + 4 x2 = 84 ... 2 x1 + 4(13) = 84 ... 2x1 + 52 = 84

(-52) 2 x1 = 32

(/2) x1 = 16

I know other people had already solved it before me and it could be solved just as easily through trial and error, but, i did it anyways as it's the 1st ever time I've found a use for algebra after constantly complaining in school that it was pointless learning it ;D

[scfcrmagic]

Fook thats confused me ......... ??? ??? ??? ???

[scfcrmagic]

Had it sorted until it was explained to me.....I copied off Beardy ....problem solved ... ;D ;D ;D ;D

[StokieMatt]

Mar 6, 2010 9:53:17 GMT scfcrmagic said:

Had it sorted until it was explained to me.....I copied off Beardy ....problem solved ... ;D ;D ;D ;D

or ask them jump

[Malex]

Mar 6, 2010 9:11:58 GMT scfcrmagic said:

Fook thats confused me ......... ??? ??? ??? ???

Sorry! I'll try and explain better, though You might want to save reading it for a time that you're suffering from insomnia or something

Both emus and elephants have 2 eyes, therefore:

2 eyes multiplied by the number of emus plus 2 eyes multiplied by the number of elephants = 58, the total number of eyes

Emus have 2 feet and elephants have 4 feet, therefore:

2 feet multiplied by the number of emus plus 4 feet multiplied by the number of elephants = 84, the total number of legs

Because Emus have both 2 eyes and 2 feet it is easy to remove them from the problem for the time being, meaning that you can work out the number of elephants. This is done by subtracting the equation for the number of eyes from the equation for the number of feet, leaving:

2 eyes multiplied by the number of elephants = 26

This gives us twice as many elephants though because each elephant has 2 eyes so compensate for this by dividing the equation by 2, basically counting each pair of eyes rather than each individual eye.

After dividing by 2 you get:

2 eyes multiplied by the number of elephants = 26 13

so there are 13 elephants!

Because we now know there are 13 elephants, it is easy to solve for the emus. Can do this just using the eye equation for now so again:

2 eyes multiplied by the number of emus plus 2 eyes multiplied by the number of elephants = 58, the total number of eyes

As we now know from earlier that there are 13 elephants accounting for 26 of the eyes, we can subtract from the equation to just leave the emus, so:

2 eyes multiplied by the number of emus plus 2 eyes multiplied by the number of elephants = 58, the total number of eyes 32, the number of eyes after we've ignored the ones that belong to elephants.

Again as earlier, divide this remaining equation by 2 as the eyes come in pairs, gives

2 eyes multiplied by the number of emus = 32 16

[Beardy200]

Malex don't forget that Emu's and Elephants both have 2 eyes and so there must have been 29 of them in total to make 58 eyes. So as soon as you've worked out one of them you know the other by subtracting it from 29 rather than going through it all over again.

[StokieMatt]

or just ask them jump and count the ones that can