Math Problem Statement

Dalam sebuah kotak terdapat 4 bola merah dan 2 bola putih, diambil 2 bola satu persatu tanpa dikembalikan. Tentukan peluang terambil: a. Berturut-turut bola merah dan putih. b. Kedua bola berwarna sama.

Solution

The image contains a probability question in Indonesian. Here’s a translation and breakdown of the problem:


Problem Statement:

  1. In a box, there are 4 red balls and 2 white balls. Two balls are drawn one at a time without replacement. Determine the probability of the following events:

    a. The two balls drawn are one red and one white.

    b. The two balls drawn are both of the same color.


Let's solve each part.

Part a: Probability of One Red and One White Ball

To find the probability of drawing one red and one white ball in two draws without replacement, we have two cases:

  1. First draw: Red, Second draw: White
  2. First draw: White, Second draw: Red

Case 1: Red first, then White

  • Probability of drawing a red ball first: 46=23\frac{4}{6} = \frac{2}{3}
  • Probability of drawing a white ball second: 25\frac{2}{5} (since one red ball is already drawn)

The probability for this case is: P(Red, then White)=23×25=415P(\text{Red, then White}) = \frac{2}{3} \times \frac{2}{5} = \frac{4}{15}

Case 2: White first, then Red

  • Probability of drawing a white ball first: 26=13\frac{2}{6} = \frac{1}{3}
  • Probability of drawing a red ball second: 45\frac{4}{5} (since one white ball is already drawn)

The probability for this case is: P(White, then Red)=13×45=415P(\text{White, then Red}) = \frac{1}{3} \times \frac{4}{5} = \frac{4}{15}

Adding both cases, the total probability of drawing one red and one white is: P(One Red and One White)=415+415=815P(\text{One Red and One White}) = \frac{4}{15} + \frac{4}{15} = \frac{8}{15}

Part b: Probability of Both Balls Being the Same Color

This scenario involves two cases as well:

  1. Both balls are red.
  2. Both balls are white.

Case 1: Both Balls Are Red

  • Probability of drawing a red ball first: 46=23\frac{4}{6} = \frac{2}{3}
  • Probability of drawing another red ball second: 35\frac{3}{5} (since one red ball is already drawn)

The probability for this case is: P(Both Red)=23×35=615=25P(\text{Both Red}) = \frac{2}{3} \times \frac{3}{5} = \frac{6}{15} = \frac{2}{5}

Case 2: Both Balls Are White

  • Probability of drawing a white ball first: 26=13\frac{2}{6} = \frac{1}{3}
  • Probability of drawing another white ball second: 15\frac{1}{5} (since one white ball is already drawn)

The probability for this case is: P(Both White)=13×15=115P(\text{Both White}) = \frac{1}{3} \times \frac{1}{5} = \frac{1}{15}

Adding both cases, the total probability of drawing two balls of the same color is: P(Same Color)=25+115=615+115=715P(\text{Same Color}) = \frac{2}{5} + \frac{1}{15} = \frac{6}{15} + \frac{1}{15} = \frac{7}{15}


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Math Problem Analysis

Mathematical Concepts

Probability
Combinatorics

Formulas

P(A and B) = P(A) * P(B|A)
Total outcomes for drawing 2 balls = 6C2

Theorems

Conditional Probability

Suitable Grade Level

Grades 10-12