Hengshui weather post

(i) Let A represent the event "rainy and snowy day", B represent the event "non-rainy and snowy day" and C represent the event "taking a taxi to work".

P(C)=P(AC)+P(BC)

=P(A)P(C/A)+P(B)P(C/B)？ ... (2 points)

= 194+36 1 128× 12+( 1? 194+361128) ×10% ≈ 0.2× 0.5+0.8× 0.1= 0.18 ... (4 points

(ii) The possible values of x are 0, 2, 20, 40, ... (6 points).

p(X = 0)=( 1- 194+36 1 128)×90%≈0.8×0.9 = 0.72，

p(X = 2)= 194+36 1 128× 12≈0.2×0.5 = 0. 1，

P(X=20)=( 1？ 194+36 1 128)× 10%≈0.8×0. 1=0.08,

P (x = 40) =194+36112 ≈ 0.2× 0.5 = 0.1,…( 10).

∴X's distribution list is

X022040p0.720.100.080.10ex = 0× 0.72+2× 0.1+20× 0.08+40× 0.1= 5.80 (Yuan ...