Answer :

AL2006
$1.12 / 12 eggs = x / 3 eggs

Cross-multiply:   

($1.12 times 3 eggs) = ('x' times 12 eggs)

3.36 dollar-eggs = 12x eggs

Divide each side by 12 eggs :

3.36 dollar-eggs / 12 eggs = x

x = 0.28 dollar