Two cards are chosen in order from a deck. In how many ways can this be done if a) the first card must be a spade and the second must be a heart b) both cards must be spades?

Milk and ice cream are mixed together for a recipe. the total volume of the mixture is 1 cup. if the milk contains 2% fat, the cream contains 18% fat ,and the mixture contains 6% fat ,how much cream is in the mixture