60 Eyes and 86 Feet

Date: 09/30/97 at 00:54:39
From: Desiree Lewellen
Subject: Eyes and feet

A zookeeper was asked how many camels and ostriches were in the zoo.  
The zookeeper answered, "Among the animals there are 60 eyes and 86 
feet." 

How many of each kind of animal were there?

I divided 60 by two and got 30 animals. What do I do with the feet?

Date: 09/30/97 at 07:56:15
From: Doctor Anthony
Subject: Re: Eyes and feet

You were correct in dividing the number of eyes by 2 to get the total 
number of animals.

So number of animals = 60/2 = 30.

Now for this type of problem use a letter to represent a number you 
don't know. Suppose that we let x = number of camels. Then since the 
total number of animals = 30, we can say 30 - x = the number of 
ostriches.

We can now write down an equation for the total number of legs, with 4 
legs for each camel and 2 legs for each ostrich.

     4x + 2(30-x) = 86

     4x + 60 - 2x = 86

               2x = 86-60

               2x = 26

                x = 13

This means there are 13 camels and 17 ostriches.

Check if this gives correct number of legs.  4 x 13 + 2 x 17 = 86  
- which is correct.  

-Doctor Anthony,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/