F.3 MATHS 20 POINTS (V.URGENT)－rdfvjur的部落格

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F.3 MATHS 20 POINTS (V.URGENT)

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About Measures of Central tendency1. The following table shows the no. of books borrowed from the library by 40 readers in each visit.No. of books borrowed 1 2 3 4 5 6Frequency 2 12 c 2 1 fa) If the median number of books borrowed is 3.5, find the value of... 顯示更多 About Measures of Central tendency 1. The following table shows the no. of books borrowed from the library by 40 readers in each visit. No. of books borrowed 1 2 3 4 5 6 Frequency 2 12 c 2 1 f a) If the median number of books borrowed is 3.5, find the value of c. b) If the median no. of books borrowed is 6, find the possible value(s) of f. Ans a) 6 b) 21,22,23 About Probability 2.Three cards are drawn at random from a deck of playing cards. Find the probability that all are of the same suit. Ans:22/425 3.A bag contains 3 red, 4 yellow and 5 blue balls. Balls are drawn at random from the bag without replacement. If two balls are drawn, find the probability that a) both are not yellow. b) only one is yellow. Ans: a)14/33 b)16/33 4. In room A, there are 4 women and 6 men, one of which is John. In room B, there are 4 men and 6 women, one of which is Mary. Now, one person is taken at random from room A and introduced into room B. The two persons are chosen at random from room B and taken into room C. Find the probability that John and Mary are both in room C. Ans:1/550 I wanna know some explanations and steps to solve the above problems THX

最佳解答:

1(a) 2 + 12 + c = 20 => c = 6(b) So, the 20 and 21st student should borrow 6 books2 + 12 + 2 + 1 = 17 => f <= 23The suitable values are 21,22,23 2 4 * C(13,3)/C(52,3)= 4 * 13!/10! * 49!/52!= (4 * 13 * 12 * 11)/(52 * 51 * 50)= (2 * 11)/(17 * 25)= 22/4253(a) C(8,2)/C(12,2)= 28/66= 14/33(b) C(4,1)C(8,1)/C(12,2)= 16/334 1/10 * 1/C(11,2)= 1/550

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