Math Problem Statement
Solution
The question in the image asks:
"You pick 2 digits (0-9) at random without replacement and write them in the order picked. What is the probability that you have written the first 2 digits of your phone number? Assume there are no repeats of digits in your phone number."
Let's break this down step by step:
Step 1: Total possible outcomes
You are selecting 2 digits from a total of 10 digits (0 through 9) without replacement.
- For the first digit, you have 10 possible choices.
- For the second digit, since you're not replacing the first one, you have 9 remaining choices.
Thus, the total number of possible outcomes is:
Step 2: Favorable outcomes
Assume the first two digits of your phone number are given. Let's call them and . Since you're only considering one specific combination of digits in that particular order (matching the first two digits of your phone number), there is only 1 favorable outcome.
Step 3: Probability
The probability is the ratio of favorable outcomes to total outcomes:
Thus, the probability that you have written the first 2 digits of your phone number is .
Would you like any further clarification or additional details?
Here are 5 related questions for further exploration:
- How would the probability change if you were to pick 3 digits instead of 2?
- What if the digits were picked with replacement? How would the probability differ?
- How would the probability be affected if the first digit couldn't be zero?
- How does the concept of permutations apply to this problem?
- Can you generalize this problem to a phone number with more than two digits?
Tip: Always pay attention to whether the problem involves replacement or not, as this significantly impacts the total number of possible outcomes.
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Math Problem Analysis
Mathematical Concepts
Probability
Combinatorics
Formulas
Total outcomes = 10 × 9
Probability = Favorable outcomes / Total outcomes
Theorems
Basic Probability Theorem
Suitable Grade Level
Grades 8-10
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