In a class of 38 students each student study at least once of the following subjects French mathematics and history the following stable give further details of the subject studies French only 9 mathematics 8 history honey one French and mathematics 7 French and history 9 history and mathematics 8

A if x is the number of students who state all the three subjects illustrate the above information in a venn diagram
ii. write an equation in x involving the number of students in the region of the diagram

1 answer

To analyze the problem, we can define the sets based on the subjects studied by the students in the class. Let's denote:

  • \( F \) for the set of students studying French
  • \( M \) for the set of students studying Mathematics
  • \( H \) for the set of students studying History

We can denote:

  • \( |F| \) = number of students studying French
  • \( |M| \) = number of students studying Mathematics
  • \( |H| \) = number of students studying History

From the information provided, we can summarize the students studying only one subject and those studying combinations of subjects as follows:

  1. Students studying only French: \( |F| - (FM + FH + FMH) = 9 \)
  2. Students studying only Mathematics: \( |M| - (FM + HM + FMH) = 8 \)
  3. Students studying only History: \( |H| - (FH + HM + FMH) = 1 \)
  4. Students studying both French and Mathematics but not History: \( |FM| = 7 \)
  5. Students studying both French and History but not Mathematics: \( |FH| = 9 \)
  6. Students studying both History and Mathematics but not French: \( |HM| = 8 \)
  7. Students studying all three subjects: \( |FMH| = x \)

Now, we also know that the total number of students studying at least one subject is: \[ |F \cup M \cup H| = 38 \]

Let's put this information into a Venn diagram representation and create an equation.

Venn Diagram Set Notation

We can denote:

  • \( |F \cap M| = 7 + x \) (French and Mathematics, including those studying all three)
  • \( |F \cap H| = 9 + x \) (French and History, including those studying all three)
  • \( |M \cap H| = 8 + x \) (Mathematics and History, including those studying all three)

Using the principle of inclusion-exclusion for three sets: \[ |F \cup M \cup H| = |F| + |M| + |H| - |F \cap M| - |F \cap H| - |M \cap H| + |F \cap M \cap H| \]

Substituting what we have, we can express the total number of students as: \[ 38 = (9 + (7 + x) + (9 + x) + (8 + x)) - (7 + x) - (9 + x) - (8 + x) + x \]

Setting up the equation

Simplifying the equation: \[ 38 = (9 + 7 + 9 + 8 + 2x) - (7 + 9 + 8 + 2x) + x \] \[ = 33 + 2x - 24 - 2x + x \] \[ = 33 - 24 + x \] \[ = 9 + x \]

Thus, our equation would be: \[ 9 + x = 38 \]

Taking \( x \) to one side gives: \[ x = 38 - 9 \] \[ x = 29 \]

Final Answer

  1. The value of \( x \) is 29, meaning 29 students are studying all three subjects.
  2. The equation that illustrates the relationship in terms of \( x \) is: \[ 38 = 9 + 7 + 8 + 1 + 9 + 8 + x \]

Note

Please double-check calculations if you re-evaluate combinations to ensure we classify students in various subject categories correctly. It’s also important to visualize through a Venn diagram for clarity on student representation in each intersection.