題組內容

四、A deck of cards has 52 cards in total. Half of the deck is red and half is black.
A quarter of the deck has the symbol hearts, a quarter has the symbol
diamonds, a quarter has the symbol spades, and a quarter has the symbol
clubs. How many ways are there to pick 15 cards if:

(a) You wish to pick an even number of black cards and an odd number of red cards? (10%)