Solve.
-$y$ varies inversely as $x$. If $y = \frac { 7 } { 2 }$ when $x = 9$, find $y$ when $x = 10$.
A) $\frac { 81 } { 50 }$
B) 5
C) $\frac { 1 } { 5 }$
D) $\frac { 81 } { 20 }$

Question

Quizplus · Accepted Answer

Since $y$ varies inversely with $x$, we know that $xy = k$ for some nonzero constant $k$. Plugging in the values given, we get:
$$\frac{7}{2} \cdot 9 = k \Rightarrow k = \frac{63}{2}$$
So, the equation relating $x$ and $y$ is $xy = \frac{63}{2}$. Now, we can plug in $x = 10$ to find $y$:
$$10y = \frac{63}{2} \Rightarrow y = \frac{63}{20} = \boxed{\textbf{(D)}\ \frac{81}{20}}$$

Solve - yyy Varies Inversely As xxx If y=72y = \frac { 7 } { 2 }y=27​

Solve
- $y$ Varies Inversely As $x$ If $y = \frac { 7 } { 2 }$