« Web Monday - in Germany | Main | Fowl play »
February 28, 2006
Cows, horses and sheep
There are cows, horses and sheep on a meadow. Not counting the cows, there are 12 animals. Not counting the horses, there are 22 animals. Not counting the sheep there are 26 animals.
How many animals of each kind are there on the meadow. You may only solve this using educated guesswork and trying to arrive at a solution by adapting your guess (i.e. no computer, no algebra). How did you get to the solution?
(This is one of my daughter's - age 10 - maths homework for today)
Update: And don't read the comments before trying.
Posted by Matthew at February 28, 2006 05:32 PM
Comments
There are 18 cows, 8 horses and 4 sheep. Do I pass 4th grade math? ;)
There are 26 between cows and horses, and cows must be much more than horses, if not counting cows there are 12 animals. I guessed 20 cows and 6 horses, which would give me 6 sheep, but that's wrong, as there would be 26 animals not counting horses. So I took a couple cows away and came up with 18 cows and 8 horses, which gives me 4 sheep and, incidentally, is the correct answer.
Posted by: Ugo Cei at February 28, 2006 07:38 PM
Ehm, why are you all guessing? It's pretty obvious from the last two pieces of information that there are 4 more horses than sheep (26 minus 22). As they sum up to 12, you just take 4 away from 12, divide it by two and know that there are 4 sheeps and 4+4 horses. And then you know instantly that there are 18 cows. That's really doable for a ten year old, isn't it? But it should be for people over 40 :)
Posted by: The Clever Guy at February 28, 2006 09:04 PM
The really funny thing here is your Google ads for today... Sheep, anyone? ;)
Posted by: Yoav Shapira at February 28, 2006 09:18 PM
I'm afraid I had to resort to algebra ;)
Posted by: Frank Koehntopp at February 28, 2006 09:44 PM
And, and Adblock Plus users see no GoogleAds ;)
Posted by: Frank Koehntopp at February 28, 2006 09:45 PM
this is much harder than the 8th grade made test I saw floating around.
I'm not sure what fecal egg counting kit is.. (one of your ads)
Posted by: Ian at February 28, 2006 10:01 PM
lts really quite easy. Each number given is the sum of the other two kinds of animals. Add all three numbersand you have counted each animal twice. The sum is 60, so there are 30 animals in all.
So 12 non-cows means 30-12 = 18 cows.
22 non-horses means 30-22 = 8 horses.
26 non-sheep means 4 sheep.
Easy :-)
Posted by: René at March 1, 2006 12:03 AM
Algebra never seemed so tempting!
Posted by: Em at March 2, 2006 04:37 PM