Math Problem Statement

Box A contains 5 red and 3 white marbles and Box B contains 2 red and 6 white marbles. If a marble is drawn from each box, what is the probability that they are both of same colour?

Solution

Let's calculate the probability that the marbles drawn from both boxes are of the same color.

Step 1: Define the events

  • Box A contains 5 red marbles and 3 white marbles.
  • Box B contains 2 red marbles and 6 white marbles.

The possible outcomes for drawing marbles from both boxes are:

  1. Both marbles are red.
  2. Both marbles are white.

We need to find the probability of these events and then sum them up.

Step 2: Calculate probabilities for each case

Case 1: Both marbles are red

  • Probability of drawing a red marble from Box A:
    P(Red from A)=55+3=58P(\text{Red from A}) = \frac{5}{5 + 3} = \frac{5}{8}
  • Probability of drawing a red marble from Box B:
    P(Red from B)=22+6=28=14P(\text{Red from B}) = \frac{2}{2 + 6} = \frac{2}{8} = \frac{1}{4}
  • Probability that both marbles are red (independent events):
    P(Both red)=P(Red from A)×P(Red from B)=58×14=532P(\text{Both red}) = P(\text{Red from A}) \times P(\text{Red from B}) = \frac{5}{8} \times \frac{1}{4} = \frac{5}{32}

Case 2: Both marbles are white

  • Probability of drawing a white marble from Box A:
    P(White from A)=35+3=38P(\text{White from A}) = \frac{3}{5 + 3} = \frac{3}{8}
  • Probability of drawing a white marble from Box B:
    P(White from B)=62+6=68=34P(\text{White from B}) = \frac{6}{2 + 6} = \frac{6}{8} = \frac{3}{4}
  • Probability that both marbles are white (independent events):
    P(Both white)=P(White from A)×P(White from B)=38×34=932P(\text{Both white}) = P(\text{White from A}) \times P(\text{White from B}) = \frac{3}{8} \times \frac{3}{4} = \frac{9}{32}

Step 3: Total probability

The total probability that both marbles are of the same color (either both red or both white) is the sum of the two probabilities: P(Same color)=P(Both red)+P(Both white)=532+932=1432=716P(\text{Same color}) = P(\text{Both red}) + P(\text{Both white}) = \frac{5}{32} + \frac{9}{32} = \frac{14}{32} = \frac{7}{16}

Final Answer:

The probability that the marbles drawn from both boxes are of the same color is 716\frac{7}{16}.


Would you like further clarification or more examples on this? Here are some related questions:

  1. What is the probability of drawing one red and one white marble from both boxes?
  2. How does the probability change if the number of red marbles in Box A is increased?
  3. What would the probability be if the marbles were drawn without replacement from both boxes?
  4. How do the probabilities change if Box B has an equal number of red and white marbles?
  5. Can the probability of drawing marbles of the same color be greater than 12\frac{1}{2}?

Tip: When calculating probabilities for independent events, simply multiply the individual probabilities of each event occurring.

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Math Problem Analysis

Mathematical Concepts

Probability
Independent Events

Formulas

P(A and B) = P(A) × P(B) for independent events
P(Same Color) = P(Both Red) + P(Both White)

Theorems

Multiplication Rule for Independent Events

Suitable Grade Level

Grades 9-10