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Question
If x and y vary inversely as other and x = 3 when y = 8, find y when x = 4 .
Solution
\[ \text{ Since x and y vary inversely, we have: } \]
\[xy = k\]
\[\text{ For x = 3 and y = 8, we have: } \]
\[3 \times 8 = k\]
\[ \Rightarrow k = 24\]
\[ \text{ For x = 4, we have: } \]
\[4y = 24\]
\[ \Rightarrow y = \frac{24}{4}\]
\[ = 6\]
\[ \therefore y = 6\]
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