• # question_answer 5) x and y vary in inverse proportion. When x is 12, y is 3. Which of the following is not a possible pair of corresponding values of x and y?        A)  4 and 9          B)         10 and 3.6     C)  72 and 0.5     D)         5 and 6

For inverse proportion, $xy=constant$ or ${{x}_{1}}{{y}_{1}}={{x}_{2}}{{y}_{2}}$ [a] As, ${{x}_{1}}{{y}_{1}}=12\times 3=36$ ${{x}_{2}}{{y}_{2}}=4\times 9=36$ $\therefore {{x}_{1}}{{y}_{1}}={{x}_{2}}{{y}_{2}}$ [b] As, ${{x}_{1}}{{y}_{1}}=36;{{x}_{2}}{{y}_{2}}=10\times 3.6=36$ $\therefore {{x}_{1}}{{y}_{1}}={{x}_{2}}{{y}_{2}}$ [c] As, ${{x}_{1}}{{y}_{1}}=36;{{x}_{2}}{{y}_{2}}=72\times 0.5=36$ [d] As, ${{x}_{1}}{{y}_{1}}=36;{{x}_{2}}{{y}_{2}}=5\times 6=30$ $\therefore$${{x}_{1}}{{y}_{1}}\ne {{x}_{2}}{{y}_{2}}$