问题 选择题

已知某运动员每次投篮命中的概率低于40%,现采用随机模拟的方法估计该运动员三次投篮恰有两次命中的概率:先由计算器产生0到9之间取整数值的随机数,指定1,2,3,4表示命中,5,6,7,8,9,0表示不命中;再以每三个随机数为一组,代表三次投篮的结果.经随机模拟产生了如下20组随机数:

907 966 191 925 271 932 812 458

569 683 431 257 393 027 556 488

730 113 537 989

据此估计,该运动员三次投篮恰有两次命中的概率为(  )

A.0.35

B.0.25

C.0.20

D.0.15

答案

由题意知模拟三次投篮的结果,经随机模拟产生了如下20组随机数,

在20组随机数中表示三次投篮恰有两次命中的有:191、271、932、812、393.

共5组随机数,

∴所求概率为

5
20
=
1
4
=0.25.

故选B.

阅读理解

Giving Back

Fair Way

The Westborough High School golf team had taken the official photos with the state prize. The other teams, disappointed, were on the bus heading home. And then Westborough instructor Greg Rota noticed something wrong x>n one of the score cards. A 9 had been recorded as a 7. They were not the state prize winner; Wobum High had won. "No one would have known," said Wobum's instruc­tor, Bob Doran. For Rota, it wasn't a difficult decision: "The prize wasn't ours to take."

Coin Stars

"College students are lazy, but they also want to help," says University of Pennsylvania graduate Dana Hork. So she made it easy, placing cups in rooms where students could leave their spare coins, and handing out cups to first-year students to keep in their rooms. Her " Change for Change" effort has collected $40,000 for charities 慈善机构), which were decided upon by students.

Never Forgotten

A school in Massachusetts received a $ 9.5 million check from Jacques LeBermuth. But it took offi­cials several days of digging to discover his connection to the school. Records showed the LeBermuth came from Belgium and studied in the school in the 1920s. When his family fell on hard times, he was offered free room and board. LeBermuth became a trader, owned shares of AT&T and lived off the earnings until he died, at age 89.

60. What did Greg Rota probably do in the end?

A. Took photos of Doran.

B. Had a meeting with Doran.

C. Returned the prize to the organizer.

D. Apologized to Wobum High School.

61. Greg Rota's decision shows that he was _______.

A. honest              B. polite               C. careful              D. friendly

62. The underlined word "Change" in the second paragraph means _______.

A. Idea           B. Decision      C. Cups               D. Coins

63. What did the school officials do after receiving the check from Mr. LeBermuth?

A. They tried to find out why he gave them the money.

B. They went to Belgium to pay their respects to him.

C. They dug out the records that were buried underground.

D. They decided to offer their students free room and board.

64. Jacques LeBermuth gave the money to the school because _______.

A. the school asked for it                

B. he had no need for that much money

C. the school had helped him in the past  

D. he wanted to be remembered by the students

单项选择题 A1/A2型题