问题


There is a single choice question about high school mathematics. Answer the question by replying A, B, C or D.
Question: If x and y are directly proportional and x = 3 when y = 8, what is the value of x when y = 13?
A. 0.615
B. 4.875
C. 15
D. 34.667
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

B. 4.875
B
deepseekr1

When \( x \) and \( y \) are directly proportional, \( x = ky \), where \( k \) is the constant of proportionality. Given \( x = 3 \) when \( y = 8 \), solving \( 3 = k \cdot 8 \) gives \( k = \frac{3}{8} \). For \( y = 13 \), substitute \( k \) into the equation: \( x = \frac{3}{8} \cdot 13 = \frac{39}{8} = 4.875 \). This matches option B. Cross-verifying using proportions \( \frac{x_1}{y_1} = \frac{x_2}{y_2} \), we find \( \frac{3}{8} = \frac{x_2}{13} \), leading to the same result.

Answer: B
B
gpto1 B B
GPT-4o B. 4.875 B
llama3.1-70B-Instruct

B
B
llama3.1-405B-Instruct

B. 4.875
B
DeepSeek-Coder-V2 B. 4.875 B
Qwen2-72B-Instruct B. 4.875 B
baichuan4 Since x and y are directly proportional, we can write the equation as:

x/y = k (constant of proportionality)

We know that when x = 3, y = 8. So, we can find the value of k:

3/8 = k

Now, we can use this k value to find x when y = 13:

x/13 = 3/8

x = (3/8) * 13

x = 39/8

x = 4.875

So, the answer is B. 4.875.
B
doubao B

If x and y are directly proportional, then x/y is a constant. When x = 3 and y = 8, the constant is 3/8. When y = 13, x = (3/8) * 13 = 4.875.
B
minimax If x and y are directly proportional, then the relationship between x and y can be expressed as:

x = ky

where k is the constant of proportionality. We can find k using the given values of x and y:

x = 3 when y = 8

3 = k * 8

k = 3 / 8

Now that we have the constant of proportionality, we can find the value of x when y = 13:

x = (3 / 8) * 13

x = 39 / 8

x = 4.875

So the correct answer is:

B. 4.875
B
kimi Since x and y are directly proportional, we can express this relationship as \( x = ky \), where \( k \) is the constant of proportionality.

Given that \( x = 3 \) when \( y = 8 \), we can find \( k \) by dividing \( x \) by \( y \):
\[ k = \frac{x}{y} = \frac{3}{8} \]

Now, we want to find the value of \( x \) when \( y = 13 \). Using the same relationship, we have:
\[ x = k \cdot y = \frac{3}{8} \cdot 13 \]

Calculating this gives us:
\[ x = \frac{3 \cdot 13}{8} = \frac{39}{8} = 4.875 \]

So the correct answer is:
B. 4.875
B
wenxinyiyan B

Explanation:

Direct proportion means that as one variable increases, the other variable increases at the same rate. Mathematically, this can be expressed as x/y = k, where k is a constant.

Given that x = 3 when y = 8, we can find the constant k:

k = x/y = 3/8

Now, to find the value of x when y = 13, we use the same constant k:

x = k * y = (3/8) * 13 = 4.875

So, the answer is B. 4.875.
B
zhipu Since \( x \) and \( y \) are directly proportional, we can write the relationship as \( x = ky \), where \( k \) is the constant of proportionality.

Given \( x = 3 \) when \( y = 8 \), we can find \( k \) as follows:
\[ 3 = k \cdot 8 \]
\[ k = \frac{3}{8} \]

Now, we need to find \( x \) when \( y = 13 \):
\[ x = k \cdot y \]
\[ x = \frac{3}{8} \cdot 13 \]
\[ x = \frac{39}{8} \]
\[ x = 4.875 \]

So, the correct answer is:
B. 4.875
B
gpto1 B B
deepseekv3 To solve the problem, we use the property of direct proportionality. If \( x \) and \( y \) are directly proportional, then:

\[
x = k \cdot y
\]

where \( k \) is the constant of proportionality.

Given \( x = 3 \) when \( y = 8 \), we can find \( k \):

\[
k = \frac{x}{y} = \frac{3}{8}
\]

Now, to find the value of \( x \) when \( y = 13 \), substitute \( k \) and \( y = 13 \) into the equation:

\[
x = k \cdot y = \frac{3}{8} \cdot 13 = \frac{39}{8} = 4.875
\]

Thus, the correct answer is:

**B. 4.875**
B