$\"\"$

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$\"\"$ varies jointly as $\"\"$ and $\"\"$ , find $\"\"$ when $\"\"$ and $\"\"$ .

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If $\"\"$ when $\"\"$ and $\"\"$ .

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Consider the values are $\"\"$ and $\"\"$ .

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Find $\"\"$ .

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$\"\"$ (Joint variation)

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$\"\"$ (Substitute $\"\"$ and $\"\"$ )

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$\"\"$ (Cross multiply)

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$\"\"$ (Simplify)

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$\"\"$ (Divide each side by $\"\"$ )

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$\"\"$ (Cancel common term)

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Therefore, the value of $\"\"$ is $\"\"$ . $\"\"$

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When $\"\"$ and $\"\"$ and $\"\"$ .