Question

If $x$ and $y$ vary inversely to each other. When $x=10,y=6$. Which is not a possible pair of corresponding values of $x$ and $y$?

• A. $15$ and $4$
• B. $20$ and $3$
• C. $15$ and $30$
• D. $0.6$ and $100$

Answer 1

The correct option is C $15$ and $30$

$x\alpha \frac{1}{y}$

$x=\frac{k}{y}$

when $x=10$

$y=6$

$10=\frac{k}{6}$

$k=60$

Option (A) $x=15$

$y=4$

$15=\frac{60}{4}=15LHS=RHS$

$\left(B\right)$ $x=20$

$y=3$

$20=\frac{60}{3}=20LHS=RHS$

$\left(C\right)$ $x=15$

$y=30$

$15=\frac{60}{30}=2LHS\ne RHS$

$\left(D\right)$ $x=0.6$

$y=100$

$0.6=\frac{60}{100}=0.6LHS=RHS$