100 animals for $100
1 pig=$2.50
1 cow=$10
1 chicken=$0.50
and you have to have at least one of each animal
Just did that, look 2 posts back
add up the animals and their values.
If there are x,y,z pigs,cows,chickens, then
x+y+z = 100
2.5x + 10y + 0.5z = 100
Now just see whether there is a unique solution with all integers.