In a survey of 200 newspaper readers, 181 of them read the Daily times, 141 read the Guardian, 117 read the punch and each read at least one of the three paper. If 75 read the Daily Times and the Guardian, 60 read the Daily Times and the punch and 54 read. The guardian and the punch.

A. Draw a venn diagram to illustrate this information
B. How many readers red
i. All 3 papers
ii. Exactly two of the papers
iii. Exactly one of the paper
D. The Guardian alone

1 answer

To solve this problem, we'll set up a Venn diagram using the information provided and then derive the numbers for the various categories.

A. Venn Diagram Setup

Let:

  • \( A \) = readers of the Daily Times
  • \( B \) = readers of the Guardian
  • \( C \) = readers of the Punch

Given:

  • \( |A| = 181 \)
  • \( |B| = 141 \)
  • \( |C| = 117 \)
  • \( |A \cap B| = 75 \) (Daily Times and Guardian)
  • \( |A \cap C| = 60 \) (Daily Times and Punch)
  • \( |B \cap C| = 54 \) (Guardian and Punch)

Let \( x \) be the number of readers who read all three newspapers (i.e., \( |A \cap B \cap C| = x \)).

Step-by-Step Calculation

  1. Use Inclusion-Exclusion Principle: The total number of readers who read at least one paper can be expressed as: \[ |A \cup B \cup C| = |A| + |B| + |C| - |A \cap B| - |A \cap C| - |B \cap C| + |A \cap B \cap C| \] Since we know that \( |A \cup B \cup C| = 200 \): \[ 200 = 181 + 141 + 117 - 75 - 60 - 54 + x \]

  2. Simplifying the equation: \[ 200 = 181 + 141 + 117 - 189 + x \] \[ 200 = 250 + x \] \[ x = 200 - 250 = -50 \]

It appears there's a calculation mistake. Let's reevaluate the specific values by directly calculating the intersections.

Individual Intersections

Let:

  • \( |A \cap B \cap C| = x \)
  • Readers who read only Daily Times and Guardian: \( |A \cap B| - x = 75 - x \)
  • Readers who read only Daily Times and Punch: \( |A \cap C| - x = 60 - x \)
  • Readers who read only Guardian and Punch: \( |B \cap C| - x = 54 - x \)

Now we can find the single paper readers:

  • Readers who read only Daily Times: \[ |A| - (|A \cap B| + |A \cap C| - |A \cap B \cap C|) = 181 - [(75 - x) + (60 - x) + x] = 181 - 135 + x = 46 + x \]

  • Readers who read only Guardian: \[ |B| - (|A \cap B| + |B \cap C| - |A \cap B \cap C|) = 141 - [(75 - x) + (54 - x) + x] = 141 - 129 + x = 12 + x \]

  • Readers who read only Punch: \[ |C| - (|A \cap C| + |B \cap C| - |A \cap B \cap C|) = 117 - [(60 - x) + (54 - x) + x] = 117 - 114 + x = 3 + x \]

Sum these all together: \[ (46 + x) + (12 + x) + (3 + x) + (75 - x) + (60 - x) + (54 - x) + x = 200 \]

Combine and simplify: \[ 200 + 3x - 4x = 200 \Rightarrow -x = 0 \Rightarrow x = 0 \]

So, \( |A \cap B \cap C| = 0 \), which means no reader reads all three.

B. Answers

  1. i. All 3 papers: 0 readers read all three.

  2. ii. Exactly two of the papers:

    • Only Daily Times and Guardian: \( 75 = 75 - 0 \)
    • Only Daily Times and Punch: \( 60 = 60 - 0 \)
    • Only Guardian and Punch: \( 54 = 54 - 0 \)

    Total = 75 + 60 + 54 = 189.

  3. iii. Exactly one of the papers:

    • Only Daily Times: \( 46 + 0 = 46 \)
    • Only Guardian: \( 12 + 0 = 12 \)
    • Only Punch: \( 3 + 0 = 3 \)

    Total = 46 + 12 + 3 = 61.

  4. The Guardian alone: \[ = 12 \]

Summary:

  • Readers of all three papers: 0
  • Readers of exactly two papers: 189
  • Readers of exactly one paper: 61
  • Readers of the Guardian alone: 12

Venn Diagram:

You can illustrate with three overlapping circles labeled A (Daily Times), B (Guardian), and C (Punch) showing:

  • In the overlap of A and B but not C, put 75.
  • In the overlap of A and C but not B, put 60.
  • In the overlap of B and C but not A, put 54.
  • The outer sections would contain the counts of those reading only one paper.