Math Problem Statement

Calculate the probability for P(not(A and C)) based on the provided table.

Solution

Let's solve part B: P(not(A and C))P(\text{not}(A \text{ and } C)). Here's the step-by-step process:

Step 1: Understand the Problem

  • AA: early out
  • BB: late start
  • CC: boys
  • DD: girls
  • P(A and C)P(A \text{ and } C): the probability of being in the early out category and a boy.

"not(A and C)" means we want the probability of everything except being a boy and in the early out group.


Step 2: Identify A and CA \text{ and } C

From the table:

  • A (early out)A \text{ (early out)} and C (boys)C \text{ (boys)}: 14 students.

Thus, the number of outcomes for A and CA \text{ and } C is 1414.


Step 3: Calculate P(A and C)P(A \text{ and } C)

The total number of students is 4040. Therefore:
P(A and C)=1440.P(A \text{ and } C) = \frac{14}{40}.

Simplify the fraction:
P(A and C)=720.P(A \text{ and } C) = \frac{7}{20}.


Step 4: Calculate P(not(A and C))P(\text{not}(A \text{ and } C))

The complement of A and CA \text{ and } C is:
P(not(A and C))=1P(A and C).P(\text{not}(A \text{ and } C)) = 1 - P(A \text{ and } C).

Substitute P(A and C)=720P(A \text{ and } C) = \frac{7}{20}:
P(not(A and C))=1720.P(\text{not}(A \text{ and } C)) = 1 - \frac{7}{20}.

Convert 11 to 2020\frac{20}{20}:
P(not(A and C))=2020720=1320.P(\text{not}(A \text{ and } C)) = \frac{20}{20} - \frac{7}{20} = \frac{13}{20}.


Step 5: Convert to Decimal

To convert 1320\frac{13}{20} to a decimal:
1320=0.65.\frac{13}{20} = 0.65.


Final Answer:

  • Simplified Fraction: 1320\frac{13}{20}
  • Decimal: 0.650.65

Let me know if you need clarification or further explanation!


Related Questions:

  1. What is P(not(B and D))P(\text{not}(B \text{ and } D))?
  2. Calculate P(A or D)P(A \text{ or } D).
  3. Find the probability of being a girl and late start.
  4. What is P(A and D)P(A \text{ and } D)?
  5. Calculate the complement of P(B and C)P(B \text{ and } C).

Tip: Always remember that probabilities of complements add up to 11. Use this when calculating "not" events!

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Math Problem Analysis

Mathematical Concepts

Probability
Complementary Events
Fractions to Decimals

Formulas

P(not E) = 1 - P(E)
Fraction simplification

Theorems

Complement Rule in Probability

Suitable Grade Level

Grades 6-8