. Z; {$ i. r. t6 a" i 8 @$ H# u7 {. G4 D5 T% v! INo.11 # E1 G/ ?/ i9 `2 |- ^ q; e+ g
(1) When events A and B are independent, P(A and B) = P(A)P(B) + y. U/ V( c" c9 z- \9 y(2) " @" ^; q" o y, P, @: l. \7a + 77b = 350 -----> a + 11b = 50# ?: O: E' f1 v
n = a + b = 50 - 11b + b = 50 -10b3 z4 S2 Q$ M3 H( `* W1 l
so n = 50 or 40 or 30 or 20 or 10