Answer:
Cooper needs 39.8 ml of milk for this recipe.
Explanation:
Cooper needs a total of 70.4 ml of milk and melted butter for a special dessert.
Let m be the amount of milk and 30.6 ml of butter be needed to prepare a dish then
m + 30.6 = 70.4
m = 70.4 - 30.6
m = 39.8 ml
Therefore, Cooper needs 39.8 ml of milk for this recipe.