Math Problem Statement

There is a 3/8 chance that it will rain on one day. Find the probability that, over two days, it rains on exactly one of those days

Solution

To solve this problem, we need to calculate the probability that it will rain on exactly one of two days, given that the probability of rain on any single day is 38\frac{3}{8}.

Let's define the events:

  • Let P(Rain)=38P(\text{Rain}) = \frac{3}{8} be the probability that it rains on a given day.
  • Let P(No Rain)=1P(Rain)=138=58P(\text{No Rain}) = 1 - P(\text{Rain}) = 1 - \frac{3}{8} = \frac{5}{8} be the probability that it does not rain on a given day.

We want to find the probability that it rains on exactly one of the two days. There are two possible scenarios:

  1. It rains on the first day and does not rain on the second day.
  2. It does not rain on the first day, but it rains on the second day.

Calculation

  1. Probability that it rains on the first day and does not rain on the second day:

    P(Rain on Day 1 and No Rain on Day 2)=P(Rain)×P(No Rain)=38×58P(\text{Rain on Day 1 and No Rain on Day 2}) = P(\text{Rain}) \times P(\text{No Rain}) = \frac{3}{8} \times \frac{5}{8}

    =1564= \frac{15}{64}

  2. Probability that it does not rain on the first day, but it rains on the second day:

    P(No Rain on Day 1 and Rain on Day 2)=P(No Rain)×P(Rain)=58×38P(\text{No Rain on Day 1 and Rain on Day 2}) = P(\text{No Rain}) \times P(\text{Rain}) = \frac{5}{8} \times \frac{3}{8}

    =1564= \frac{15}{64}

Adding the Probabilities

To find the probability that it rains on exactly one of the two days, we add the probabilities of the two scenarios:

P(Exactly one rainy day)=1564+1564=3064P(\text{Exactly one rainy day}) = \frac{15}{64} + \frac{15}{64} = \frac{30}{64}

=1532= \frac{15}{32}

Conclusion

The probability that it rains on exactly one of the two days is 1532\frac{15}{32}.

Would you like more details or have any questions?

Here are 5 related questions you might find interesting:

  1. What is the probability that it rains on both days?
  2. What is the probability that it does not rain on either of the two days?
  3. If the probability of rain changes to 12\frac{1}{2}, what would the probability be that it rains on exactly one of the two days?
  4. How would the probability change if we considered three days instead of two?
  5. What is the expected number of rainy days over a two-day period with the given probability?

Tip: When dealing with multiple independent events, consider each possible scenario separately, calculate their probabilities, and then combine them according to the problem requirements.

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Math Problem Analysis

Mathematical Concepts

Probability Theory

Formulas

Probability of independent events

Theorems

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Suitable Grade Level

Grades 9-12