问题


There is a single choice question about high school mathematics. Answer the question by replying A, B, C or D.
Question: Express as a common fraction the reciprocal of $0.\overline7$.
A. \frac{7}{2}
B. \frac{7}{9}
C. \frac{9}{2}
D. \frac{9}{7}
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

D. \frac{9}{7}
D
deepseekr1

To convert \(0.\overline{7}\) to a fraction, let \(x = 0.\overline{7}\). Multiplying both sides by 10 gives \(10x = 7.\overline{7}\). Subtracting the original equation from this result:
\(10x - x = 7.\overline{7} - 0.\overline{7}\)
\(9x = 7\)
\(x = \frac{7}{9}\).

The reciprocal of \(\frac{7}{9}\) is \(\frac{9}{7}\).

**Answer:** D. \(\frac{9}{7}\)
D
gpto1 D D
GPT-4o To find the reciprocal of \( 0.\overline{7} \), we first need to express \( 0.\overline{7} \) as a fraction.

Let \( x = 0.\overline{7} \).

Then, \( 10x = 7.\overline{7} \).

Subtract \( x \) from \( 10x \):

\( 10x - x = 7.\overline{7} - 0.\overline{7} \)

\( 9x = 7 \)

So, \( x = \frac{7}{9} \).

The reciprocal of \( \frac{7}{9} \) is \( \frac{9}{7} \).

Therefore, the correct answer is:

D. \(\frac{9}{7}\)
D
llama3.1-70B-Instruct

B
The best answer is B.
D
llama3.1-405B-Instruct

D. To find the reciprocal of $0.\overline7$, first convert $0.\overline7$ to a common fraction. Let $x=0.\overline7$. Since $0.\overline7$ has one digit, multiply both sides of the equation by 10 to get $10x=7.\overline7$. Subtracting the equation $x=0.\overline7$ from $10x=7.\overline7$ yields $9x=7$, or $x=\frac{7}{9}$. Therefore, the reciprocal of $0.\overline7$ is $\frac{9}{7}$.
The best answer is D.
D
DeepSeek-Coder-V2 To solve the problem of finding the reciprocal of \(0.\overline{7}\), we need to follow these steps:

1. **Express \(0.\overline{7}\) as a fraction:**
Let \(x = 0.\overline{7}\).

2. **Multiply both sides by 10 to shift the decimal point:**
\(10x = 7.\overline{7}\).

3. **Subtract the original equation from this new equation:**
\[
10x - x = 7.\overline{7} - 0.\overline{7}
\]
\[
9x = 7
\]

4. **Solve for \(x\):**
\[
x = \frac{7}{9}
\]

5. **Find the reciprocal of \(\frac{7}{9}\):**
The reciprocal of \(\frac{7}{9}\) is \(\frac{9}{7}\).

Thus, the answer is \(\boxed{D}\).
D
Qwen2-72B-Instruct B. \frac{7}{9} D
baichuan4 D D
doubao Let x = 0.7777...
10x = 7.7777...
10x - x = 7.7777... - 0.7777...
9x = 7
x = 7/9
The reciprocal of 7/9 is 9/7.
So the answer is D.
D
minimax Let's denote $0.\overline{7}$ as $x$. This means that $x = 0.7777...$.

To convert this repeating decimal into a fraction, we can use the following trick:

Multiply $x$ by 10 to shift the decimal point one place to the right, so we get $10x = 7.7777...$.

Now, subtract $x$ from $10x$ to eliminate the repeating decimals:

$10x - x = 7.7777... - 0.7777...$

$9x = 7$

Now, solve for $x$:

$x = \frac{7}{9}$

The reciprocal of $x$ is the fraction flipped over, so the reciprocal of $0.\overline{7}$ is $\frac{9}{7}$.

The correct answer is:

D. $\frac{9}{7}$
D
kimi To express the reciprocal of \(0.\overline{7}\) as a common fraction, we first need to convert \(0.\overline{7}\) into a fraction.

Let \(x = 0.\overline{7}\). Then, multiplying both sides by 10, we get \(10x = 7.\overline{7}\).

Now, subtract the original \(x\) from this equation:
\[10x - x = 7.\overline{7} - 0.\overline{7}\]
\[9x = 7\]

So, \(x = \frac{7}{9}\).

The reciprocal of \(\frac{7}{9}\) is \(\frac{9}{7}\).

Answer: D. \(\frac{9}{7}\)
D
wenxinyiyan D D
zhipu To solve this problem, we need to first convert the repeating decimal \(0.\overline{7}\) to a fraction. Let's denote \(x = 0.\overline{7}\).

To eliminate the repeating decimal, we multiply both sides of the equation by 10:
\[ 10x = 7.\overline{7} \]

Next, we subtract the original equation \(x = 0.\overline{7}\) from this new equation:
\[ 10x - x = 7.\overline{7} - 0.\overline{7} \]
\[ 9x = 7 \]

Solving for \(x\), we get:
\[ x = \frac{7}{9} \]

Now, we need to find the reciprocal of \( \frac{7}{9} \):
\[ \text{Reciprocal of } \frac{7}{9} = \frac{9}{7} \]

Thus, the answer is:
D. \(\frac{9}{7}\)
D
gpto1 D D
deepseekv3 To find the reciprocal of \( 0.\overline{7} \), follow these steps:

1. **Express \( 0.\overline{7} \) as a fraction:**
Let \( x = 0.\overline{7} \).

Multiply both sides by 10:
\[
10x = 7.\overline{7}
\]

Subtract the original equation:
\[
10x - x = 7.\overline{7} - 0.\overline{7}
\]
\[
9x = 7
\]

Solve for \( x \):
\[
x = \frac{7}{9}
\]

So, \( 0.\overline{7} = \frac{7}{9} \).

2. **Find the reciprocal of \( \frac{7}{9} \):**
The reciprocal of a fraction \( \frac{a}{b} \) is \( \frac{b}{a} \).

Therefore, the reciprocal of \( \frac{7}{9} \) is:
\[
\frac{9}{7}
\]

**Answer:** \(\boxed{D}\)
D