[計量] 好多題數學請教
先說抱歉 因為不會做的題目實在很多...
1. After the decimal point is moved to its right six spaces, the positive
decimal x will then be nine times the reciprocal of the original decimal x.
What is the original decimal x? (填充) 答案:0.003 請問這怎麼求出來的?
2. A bag contains 5 red balls and 5 blue balls. In how many ways can 5 balls
be drawn at random such that there are at least two balls of each colour?
(多選) A. 200 B. 2*C(5,2)*C(5,3) C. 100 D. C(5,2)*C(5,3) E. C(10,5)
我是想說有兩種情況:
(情況一) 紅2藍3 所以C(5,2)*C(5,3)
(情況二) 藍2紅3 所以也是C(5,2)*C(5,3)
然後相乘得100 所以答案是C跟D, 但是答案卻是A跟B...
請問我是哪邊出錯呢?
3. How many different 6-letters sequences are there that consist of 1 A,
2 B's, and 3 C's? (填充) 答案:60
可是我是算6!...可能是我理解題目有誤...
4. If 3^6x=8,100, what is the value of (3^x-1)^3? (單選) 答案是D 請問怎做?
A.90 B.30 C.10 D.10/3 E.10/9
5. If n is a positive number, what is the remainder when (7^4n+3)(6^n) is
divided by 10? (單選) 答案是E 這題也是想知道要怎麼做
A. 1 B. 2 C. 4 D. 6 E. 8
看來我好像關於指數那部分很糟糕啊XDD
然後不排除答案有誤...因為是補習班習題 只有題目跟解答 沒有解題說明
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※ 編輯: grassroots (114.25.141.18), 09/05/2018 21:35:00
推
09/05 22:47,
6年前
, 1F
09/05 22:47, 1F
推
09/05 23:38,
6年前
, 2F
09/05 23:38, 2F
喔對吼 回去看高中課本才看到不盡相異物排列的算法...感謝!
推
09/06 00:08,
6年前
, 3F
09/06 00:08, 3F
→
09/06 00:09,
6年前
, 4F
09/06 00:09, 4F
→
09/06 00:10,
6年前
, 5F
09/06 00:10, 5F
→
09/06 00:11,
6年前
, 6F
09/06 00:11, 6F
→
09/06 00:12,
6年前
, 7F
09/06 00:12, 7F
→
09/06 00:13,
6年前
, 8F
09/06 00:13, 8F
→
09/06 00:14,
6年前
, 9F
09/06 00:14, 9F
→
09/06 00:15,
6年前
, 10F
09/06 00:15, 10F
推
09/06 00:19,
6年前
, 11F
09/06 00:19, 11F
→
09/06 00:20,
6年前
, 12F
09/06 00:20, 12F
→
09/06 00:21,
6年前
, 13F
09/06 00:21, 13F
→
09/06 00:22,
6年前
, 14F
09/06 00:22, 14F
→
09/06 00:23,
6年前
, 15F
09/06 00:23, 15F
→
09/06 00:23,
6年前
, 16F
09/06 00:23, 16F
推
09/06 00:35,
6年前
, 17F
09/06 00:35, 17F
→
09/06 00:36,
6年前
, 18F
09/06 00:36, 18F
→
09/06 00:36,
6年前
, 19F
09/06 00:36, 19F
感謝b大!是不是這種關於指數的題目很多時候都是考找規律之類的解法啊?
我完全沒sense啊(掩面...
推
09/06 12:12,
6年前
, 20F
09/06 12:12, 20F
太明顯了嗎XDD
※ 編輯: grassroots (61.228.129.177), 09/06/2018 13:28:34
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