2Q of F.5 maths

👨🏻‍🏫 學術台數學

[匿名]

2011-07-23 6:55 am

1. Out of 25 Form 4 students, 11 students study geog, 15 study history, 6 study both.
(a) How many study History only?
(b) How many study geog only?
(c) How many study neither?

2. In a survey, the following data concerning the subsciption of 3 magazines P,Q and R are collected:

P: 50%
Q: 45%
R: 55%
P,Q: 20%
P,R: 15%
Q,R: 25%
P,Q,R: 5%

(a) What % subscribes exactly 2 magazines?
(b) What % subscribes at least 2 magazines?
(c) What % does not subscribe any of the 3 magazines?

更新1:

but i don't know how to draw the Venn diagram....= =

回答 (2)

myisland8132

2011-07-23 5:31 pm

✔ 最佳答案

1 n(G) = 11, n(H) = 15, n(G and H) = 6

n(G or H) = 11 + 15 - 6 = 20

n(history only) = 15 - 6 = 9

(b) n(geography) = 11 - 6 = 5

(c) n( neither) = 25 - 20 = 5

2(a) % subscribes exactly 2 magazines

= (20 - 5 + 15 - 5 + 25 - 5)%

= 45%

(b) % subscribes at least 2 magazines

= (45 + 5)%

= 50%

(c) By drawing Venn diagram, there are 5 % does not subscribe any of the 3 magazines

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用戶10012

2011-07-23 2:39 pm

The simpliest way for these questions is to draw a Venn diagram based on data provided.

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