NCERT · Class 8 · Mathematics · Direct and Inverse ProportionsIf $x$ and $y$ are in direct proportion, which of the following relations is always true?
Step-by-Step Solution
When two quantities $x$ and $y$ are in direct proportion, their ratio $\frac{x}{y}$ remains constant ($k$). Therefore, $x = ky$, or $\frac{x_1}{y_1} = \frac{x_2}{y_2}$.
Detailed Options Breakdown
Option : $xy = k$
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Direct and Inverse Proportions.
Option 1: $x + y = k$
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Direct and Inverse Proportions.
Option 2: $\frac{x}{y} = k$ (Correct Answer)
Correct choice. Refer to the step-by-step verified solution guidelines above for details.
Option 3: $x - y = k$
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Direct and Inverse Proportions.
💡 Study Guide: This question tests core syllabus concepts from Direct and Inverse Proportions. For formulas, key summaries, and mock exam reference guides, read the full Direct and Inverse Proportions Revision Notes.