F3 Maths - Ans.fyi 參考答案

F3 Maths

2007-05-19 7:57 pm

A box contains 10 000 lottery tickets which are numbered from 0000 to 9999.

A ticket is drawn at random from the box. Find the probability that the number on the ticket drawn meets the following requirement.

(a) The last digit is divisible by 3.
(b) The last two digits are the same.
(c) The last three digits are 123, 456 or 789.

我識得計,但我唔識得列式.
請列式
同埋唔好用F6 d Maths and Stat的方法計
用番簡易ge F3 程度show 個solution 出來
Thx~~~

回答 (1)

用戶11400

2007-05-19 8:25 pm

✔ 最佳答案

以上問題沒有詳細的式，只需詳細說日計算機率的分子和分母是怎樣得到的，就行了。
a.
The last digit is divisible by 3, i.e. the last number is 3 or 6 or 9, total 3 possibilities,
For last digit from 0 to 9, there are total 10 numbers,
and so, the probability of last digit divisible by 3 = 3/10

b.
The last two digits are the same, i.e. the last two digits it 00, 11, 22, 33, 44, 55, 66, 77, 88 or 99, totally 10 possibilities
For last two digits from 00 to 99, there are 100 numbers,
And so the probability of last two digits are the same = 10/100 = 1/10

c.
The last three digits are 123, 456 or 789, total 3 possibilities.
For last three digits from 000 to 999, there are total 1,000 numbers,
And so the probability of last three digits are 123, 456 or 789 = 3/1000

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