Use the formula for nCr to solve Exercises 49–56. An election ballot asks voters to select three city commissioners from a group of six candidates. In how many ways can this be done?
Ch. 8 - Sequences, Induction, and Probability

9장, 문제 49
Express each repeating decimal as a fraction in lowest terms.
검증된 단계별 안내1
Let \( x = 0.257257257\ldots \), where the digits 257 repeat indefinitely.
Since the repeating block has 3 digits, multiply \( x \) by \( 10^3 = 1000 \) to shift the decimal point three places to the right: \( 1000x = 257.257257257\ldots \).
Set up the equation by subtracting the original \( x \) from this new expression to eliminate the repeating decimal part: \( 1000x - x = 257.257257257\ldots - 0.257257257\ldots \).
Simplify the subtraction to get \( 999x = 257 \), since the repeating decimals cancel out.
Solve for \( x \) by dividing both sides by 999: \( x = \frac{257}{999} \). Then, simplify the fraction to its lowest terms by finding the greatest common divisor (GCD) of 257 and 999 and dividing numerator and denominator by it.

비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
5m주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Repeating Decimals
A repeating decimal is a decimal number in which a sequence of digits repeats infinitely. For example, 0.257̅ means the digits '257' repeat endlessly. Understanding this pattern is essential to convert the decimal into a fraction.
추천 영상:
How to Graph Rational Functions
Algebraic Representation of Repeating Decimals
To convert a repeating decimal to a fraction, represent the decimal as a variable (e.g., x), then multiply by a power of 10 to shift the decimal point to align repeating parts. Subtracting these equations eliminates the repeating portion, allowing you to solve for x as a fraction.
추천 영상:
Introduction to Algebraic Expressions
Simplifying Fractions to Lowest Terms
After finding the fraction equivalent of the repeating decimal, simplify it by dividing numerator and denominator by their greatest common divisor (GCD). This ensures the fraction is expressed in its simplest form, which is a standard requirement in algebra.
추천 영상:
Radical Expressions with Fractions
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