问题 解答题

现有6张卡片,分别印有1,2,3,4,5,6六个数字,甲、乙两人合作完成两个游戏:

(1)游戏一:规则是从6张卡片中任意抽取一张,若抽到是奇数,则甲获胜,若抽到是偶数则乙获胜.你认为这个游戏公平吗?若公平,请说明理由;若不公平,请你修改游戏规则;

(2)游戏二:规则是从6张卡片中任意抽取两张,若和为奇数,则甲获胜,若和为偶数,则乙获胜.你认为这个游戏公平吗?若公平,请说明理由;若不公平,请你修改游戏规则.

答案

(1)公平(1分)

P(奇)=

3
6
=
1
2
(1分),

P(偶)=

3
6
=
1
2
(1分),

∵P(奇)=P(偶),∴游戏公平(2分)

(2)不公平(1分)

因为从6张卡片中任取两张得所有情况为:

(1,2),(1,3),(1,4),(1,5),(1,6),(2,3),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6),(4,5),(4,6),(5,6)

共15种情况,每种情况发生的可能性相同,其中和为奇数的有9种,和为偶数的有6种(1分),

P(甲)=

9
15
=
3
5
,P(乙)=
6
15
=
2
5
(1分)

3
5
2
5

∴甲获胜的机会大于乙获胜的机会.(1分)

规则修改为:在6张卡片中,任取两张,同时为奇数甲获胜,同为偶数乙获胜.(2分)

单项选择题

(B)

Eddie McKay, a once-forgotten pilot, is a subject of great interest to a group of history students in Canada.

It all started when Graham Broad, a professor at the University of Western Ontario, found McKay’s name in a footnote in a book about university history. McKay was included in a list of university alumni (校友) who had served during the First World War, but his name was unfamiliar to Broad, a specialist in military history. Out of curiosity, Broad spent hours at the local archives (档案馆) in a fruitless search for information on McKay. Tired and discouraged, he finally gave up. On his way out, Broad’s glance happened to fall on an exhibiting case showing some old newspapers. His eye was drawn to an old picture of a young man in a rugby uniform.

As he read the words beside the picture, he experienced a thrilling realization. "After looking for him all day, there he was, staring up at me out of the exhibiting case," said Broad. Excited by the find, Broad asked his students to continue his search. They combed old newspapers and other materials for clues. Gradually, a picture came into view.

Captain Alfred Edwin McKay joined the British Royal Flying Corps in 1916. He downed ten enemy planes, outlived his entire squadron(中队) as a WWI flyer, spent some time as a flying instructor in England, then returned to the front, where he was eventually shot down over Belgium and killed in December 1917. But there’s more to his story. "For a brief time in 1916 he was probably the most famous pilot in the world," says Broad. "He was credited with downing Oswald Boelcke, the most famous German pilot at the time." Yet, in a letter home, McKay refused to take credit, saying that Boelcke had actually crashed into another German plane.

McKay’s war records were destroyed during a World War II air bombing on London-an explanation for why he was all but forgotten.

But now, thanks to the efforts of Broad and his students, a marker in McKay’s memory was placed on the university grounds in November 2007. "I found my eyes filling with tears as I read the word ’deceased’ (阵亡) next to his name," said Corey Everrett, a student who found a picture of Mckay in his uniform. "This was such a simple example of the fact that he had been a student just like us, but instead of finishing his time at Western, he chose to fight and die for his country.\

What is the text mainly about()。

A. The research into war history.

B. The finding of a forgotten hero.

C. The pilots of the two world wars.

D. The importance of military studies.

单项选择题