单项选择题
假定X 是掷5次硬币国徽面朝上的次数,然后再同时掷X 次骰子。设Y 是骰子显示数目的总和,则=()。
A.4.75B.8.75C.13.50D.22.60E.31.35
A.75.043B.75.097C.75.407D.75.642E.75.781
A.0.00045B.0.00081C.0.00141D.0.00841E.1.00843
A.0.2222B.0.2321C.0.2326D.0.2423E.0.2424
A.0.107458B.0.10698C.0.10546D.0.10456E.0.10365
A.0.042B.0.049C.0.059D.0.062E.0.075
A.2/15B.1/3C.4/15D.31/110E.29/90
A.0B.-0.1C.0.1D.-0.2E.0.2
A.0.03122B.0.03129C.0.03155D.0.03158E.0.03160
A.μx+u+t =μx+t μu+tB.μx+u+t =μx+tC.μx+u+t =μx+t +μu+tD.μx+u+t =μx+t -μu+tE.μx+u+t =μx+t /μu+t
A.65.69B.66.31C.67.69D.68.31E.69.69