事件树 现在 年后 两年后概率 0.4×0.1=0.04 P=04 15 P=0.9 0.4×0.9=0.36 8 P=06 P=0.5 0.6×0.5=0.3 10 P=0.5 0.6×0.5=0.3事件树 – 现在 一年后 两年后 概率 P = 0.4 P = 0.6 1510 P = 0.9 P = 0.1 P = 0.5 P = 0.5 8 6 8 4 0.40.1= 0.04 0.40.9 = 0.36 0.60.5 = 0.3 0.60.5 = 0.3