SOLUTION: There are 70 employees in a certain firm. We know that 42 of these employees are​ male, 12 of these males are​ secretaries, and 26 secretaries are employed by the firm. What is

Algebra ->  Probability-and-statistics -> SOLUTION: There are 70 employees in a certain firm. We know that 42 of these employees are​ male, 12 of these males are​ secretaries, and 26 secretaries are employed by the firm. What is      Log On


   

Question 1138445: There are 70 employees in a certain firm. We know that 42 of these employees are​ male, 12 of these males are​ secretaries, and 26 secretaries are employed by the firm. What is the probability that an employee chosen at random is a​ secretary, given that the person is a male​?
Answer by ikleyn(52812) About Me  (Show Source):
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This conditional probability can be calculated in two ways:


    a)  As a conditional probability  %28%2812%2F70%29%29%2F%28%2842%2F70%29%29 = 12%2F42 = 2%2F7,   


or directly, based on common sense (and even without knowing the formal definition of probability, at all), as


    b)  12%2F42 = 2%2F7.


Both answers are the same.


Notice that the given part of the condition 

    "26 secretaries are employed by the firm"

is not used in the solution and is excessive and unnecessary.


It is included into the condition with the only goal to confuse a reader and to check if he (or she) knows the subject.

Solved, answered and completed.