There are a total of 100 animals: cows, sheep and buffaloes. These 100 animals ate 100 bunches of grass.

Every cow ate 5 bunches, every buffalo ate 3 bunches and every sheep ate only 1/3 bunch.

How many cow, sheep and buffalo are there? You only know that there is at least one of every kind of animal.

We have 7c + 4b = 100 after we simplified 2 these equations :
c+b+s=100 and 5c+3b+c/3=100
Aslo we have c can't be greater than 14
4b=100-7c
from that we know (100-7c) must be a number can divide by 4 without remains.
Because 100 can divide by 4, so we have 7c must be a number can divide by 4====>c must be a number can divide by 4 and less than 14=====>c=4,8,12.
from that we can know b and s
This method works all kinds of these problems. But anyway, Congratualation Ender. I have more interesting math for you. Good luck !

Posted by vohonam on 2002-06-12 18:22:39