試題詳解

233. Ten cards from a deck of playing cards are in a box: two diamonds, three spades, and five hearts. Two cards are randomly selected without replacement.

Calculate the variance of the number of diamonds selected, given that no spade is selected.
(A) 0.24
(B) 0.28
(C) 0.32
(D) 0.34
(E) 0.41