请问TT GWD Q2,Q14 (对不上汇总贴）

eggegg

Q2:

On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

 

A.    0.008

B.     0.128

C.     0.488

D.    0.512

E.     0.640

Answer: B

Q14: 

How many seconds will it take for a car that is traveling at a constant rate of 45 miles per hour to travel a distance of 22 yards?      (1 mile = 1,160 yards)

 

A.    8

B.     9

C.     10

D.    11

E.     12

Answer: C 应该是挺简单一题，但是我怎么算得1.5….

instantreply

Q2是E=0.64吧?
解釋: 第三天不管下不下雨都是當天結束在回家，所以第三天根本不用管‧
因此 0.8^2=0.64 (前兩天都要晴天 1-0.2=0.8)

Q14有誤吧....我也是算1.5....to be exact, it is 44/29

EssePain

Q14 估计是哪个数字给错了,少了个0，现在的条件算出来是等于1。

(LZ,1 mile=1760 yards, not 1160)

帝俊

Q2是B

下雨的概率p1＝0.2
不下雨的概率p2=0.8
他下周一回来说明周六周日不下雨，周一下雨。概率就是0.8*0.8*0.2=0.128

Q14

答案错误

22/(45*1160/60/60)＝1.5s

答案错误

22/(45*1160/60/60)＝1.5s

[此贴子已经被作者于2009-5-5 9:51:43编辑过]

instantreply

阿對 Q2是0.128

eggegg

明白了,谢谢instantreply, essepain,帝俊