Two dice are thrown independently.

Question

Two dice are thrown independently. $A$: number on die 1 < number on die 2; $B$: die 1 even, die 2 odd; $C$: die 1 odd, die 2 even. Then

Accepted Answer

$n(A)=15$ (pairs with first<second), $n(B)=9$, $n(C)=9$.

$$n((A\cup B)\cap C) = n(A\cap C)\cup(B\cap C) = (3+2+1)+0=6$$

So option A is correct (note $n(B)=n(C)=9$, not 6, ruling out option C).

Solutions · 1