IB數(shù)學(xué)例題解析及練習(xí)Conditional probabilities

今日知識(shí)點(diǎn)：

Conditional probabilities

例題

Q： A group of girls at a school is entered for Advanced Level Mathematics modules. Each girl takes only module M1 or only module M2 or both M1 and M2.

The probability that a girl is taking M2 given that she is taking M1 is 1/5

The probability that a girl is taking M1 given that she is taking M2 is 1/3

Find the probability that a girl selected at random is taking both M1 and M2.

解析

下面我們?yōu)榇蠹覝?zhǔn)備了一道同類(lèi)型的題目，請(qǐng)大家一起來(lái)試試解答。

Your turn

In a certain college

65% of the students are full-time students,

55% of the students are female,

35% of the students are male full-time students.

Find the probability that a student chosen at random from all the?female?students in the college is a part-time student.

Correct Answer：?0.45