If $x$ and $y$ vary directly and $y$ is 65 when $x$ is 13 , find $y$ when $x$ is 3 .
Answer Attempt 1 out of 2

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Answer

So, when $x$ is 3, $y$ is $\boxed{15}$

Steps

Step 1 ：Since $x$ and $y$ vary directly, we can say that $y = kx$ for some constant $k$.

Step 2 ：Given that $y$ is 65 when $x$ is 13, we can substitute these values into the equation to find $k$:

Step 3 ：$65 = 13k$

Step 4 ：Solving for $k$, we get $k = \frac{65}{13}$

Step 5 ：So, $k = 5$

Step 6 ：Now that we know $k$, we can find $y$ when $x$ is 3:

Step 7 ：$y = 5 * 3$

Step 8 ：$y = 15$

Step 9 ：So, when $x$ is 3, $y$ is $\boxed{15}$