close
標題:

S5 math Probability re ex

發問:

From place A to place B, there are 3 bus routes and 2 minibus routes available. From place B to place C,there are 2 bus routes and 1 minibus route availablea)in how many ways can Mr Lee travel from place A to place B and then from place B to place C (ans : 15)Find the number of odd numbers between 300 and... 顯示更多 From place A to place B, there are 3 bus routes and 2 minibus routes available. From place B to place C,there are 2 bus routes and 1 minibus route available a)in how many ways can Mr Lee travel from place A to place B and then from place B to place C (ans : 15) Find the number of odd numbers between 300 and 800, whose digits are all distinct (ans: 176) How many odd numbers between 300 and 800 can be formed from 0,1,4,5,6,8 and 9 without repetition? (ans : 40) How many 4-digit even numbers can be formed from 3,4,5,6 and 9 without repetition?(ans: 48) How many 3-digit numbers that are greater than 400 can be formed from 0 to 9 without repetition?(ans: 360) 10 students are siting for an oral test. They are divided into two groups and then sit around two tables A and B. If each table has 5 seats numbered 1 to 5, find the number of ways of seating (ans: 3628800)

最佳解答:

 

此文章來自奇摩知識+如有不便請留言告知

1. No. of required ways = (3 + 2) x (2 + 1) = 5 x 3 = 15 ===== 2. Case 1 : The 100s digit is 4, 6 (2) The 1s digit is 1, 3, 5, 7, 9 (5) Case 2 : The 100s digit is 3, 5 or 7. (3) The 1s digit is 1, 3, 5, 7 or 9, but not the 100s digit. (4) Lastly, The 10s digit is from 0 to 9, but not the 100s or 1s digit. (8) No. of required odd numbers = (2 x 5 + 3 x 4) x 8 = 176 ===== 3. Case 1 : The 100s digit is 4 or 6 (2) The 1s digit is 1, 5 or 9 (3) Case 2 : The 100s digit is 5. (1) The 1s digit is 1 or 9. (2) Lastly, the 10s digit is a digit from 0,1,4,5,6,8 or 9, but not the 100s or 1sdigit. (5) No. of required odd numbers = (2 x 3 + 1 x 2) x 5 = 40 ===== 4. Case 1 : The 1000s digit is 4 or 6 (2) The 1s digit is 4 or 6, but not the 100s digit. (1) Case 2 : The 1000s digit is 3, 5 or 9. (3) The 1s digit is 4 or 6. (2) Lastly, The 10s digit is a digit from 3,4,5,6 or 9, but not the 1000sor 1s digit. (3) The 100s digit can be a digit from 3,4,5,6or 9, but not the 1000s, 10s or 1s digit. (2) No. of required odd numbers = (2 x 1 + 3 x 2) x 3 x 2 = 48 ===== 5. The 100s digit is from 4 to 9. (6) The 1s digit is from 0 to 9, but not the 100s digit. (9) The 10s digit is from 0 to 9, but not the 100s or 1s digit. (8) No. of 3-digit numbers = 6 x 9 x 8 = 432 (The given answer is incorrect.) (If it is "greater than 500", the answer is 360. ===== 6. From the 10 students, choose 5 students to sit around table A (10C5). The rest 5 students sit around table B (5C5). Arrange numbers 1 to 5 for the students at each table of A and B. (5P5-2) Required no. of ways = 10C5 x 5C5 x 5P52 = 3628800

其他解答:7C4150FCDCEDD023
arrow
arrow
    文章標籤
    更多 何準備 任何數 公式 文章
    全站熱搜

    gpjqem1 發表在 痞客邦 留言(0) 人氣()

    E-mail轉寄