Question

甲乙两市一年中雨天比例分别占0.2和0.14,两市同时下雨是0.12.(1)求乙市不下雨时,甲市也不下雨的概率.

Answer 1

(1)求乙市不下雨时,甲市也不下雨的概率是

1-(0.2-0.12)/(1-0.14)=1-0.08/0.86=1-0.093023256=0.906976744

或

(1-0.2-0.14+0.12)/(1-0.14)=0.78/0.86=0.906976744

(2)至少有一市不下雨的概率是

1-0.12=0.88