Respuesta :

Given:

Total number of students = 27

Students who play basketball = 7

Student who play baseball = 18

Students who play neither sports = 7

To find:

The probability the student chosen at randomly from the class plays both basketball and base ball.

Solution:

Let the following events,

A : Student plays basketball

B : Student plays baseball

U : Union set or all students.

Then according to given information,

[tex]n(U)=27[/tex]

[tex]n(A)=7[/tex]

[tex]n(B)=18[/tex]

[tex]n(A'\cap B')=7[/tex]

We know that,

[tex]n(A\cup B)=n(U)-n(A'\cap B')[/tex]

[tex]n(A\cup B)=27-7[/tex]

[tex]n(A\cup B)=20[/tex]

Now,

[tex]n(A\cup B)=n(A)+n(B)-n(A\cap B)[/tex]

[tex]20=7+18-n(A\cap B)[/tex]

[tex]n(A\cap B)=7+18-20[/tex]

[tex]n(A\cap B)=25-20[/tex]

[tex]n(A\cap B)=5[/tex]

It means, the number of students who play both sports is 5.

The probability the student chosen at randomly from the class plays both basketball and base ball is

[tex]\text{Probability}=\dfrac{\text{Number of students who play both sports}}{\text{Total number of students}}[/tex]

[tex]\text{Probability}=\dfrac{5}{27}[/tex]

Therefore, the required probability is [tex]\dfrac{5}{27}[/tex].

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