The value of y varies directly with x

The Correct Answer and Explanation is:

Correct Answer: 1 5/7

📘 Explanation

This problem involves the concept of direct variation, which describes a relationship between two variables where one is a constant multiple of the other. Mathematically, this is expressed as:

y=kxy = kx

Here, yy varies directly with xx, meaning the ratio yx\frac{y}{x} remains constant. This constant is denoted by kk, the constant of variation.

We are given:

  • y=247y = 2 \frac{4}{7}
  • x=37x = \frac{3}{7}

First, convert the mixed number y=247y = 2 \frac{4}{7} into an improper fraction:

247=1872 \frac{4}{7} = \frac{18}{7}

Now, calculate the constant of variation kk:

k=yx=187÷37=187×73=12621=6k = \frac{y}{x} = \frac{18}{7} \div \frac{3}{7} = \frac{18}{7} \times \frac{7}{3} = \frac{126}{21} = 6

So, k=6k = 6. This means for any value of xx, the corresponding value of yy is 6x6x.

Now, we are asked to find the value of yy when x=27x = \frac{2}{7}:

y=6×27=127y = 6 \times \frac{2}{7} = \frac{12}{7}

Convert 127\frac{12}{7} into a mixed number:

127=157\frac{12}{7} = 1 \frac{5}{7}

Thus, the value of yy when x=27x = \frac{2}{7} is 1 5/7.

This solution demonstrates how direct variation allows us to maintain a consistent relationship between variables. By finding the constant of variation, we can easily compute new values without needing a graph or table.

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