Question

If x varies inversely with y and x = 8 when y = 6, find y when x = 10.

A. y = 4.8
B. y = 7.5
C. y = 40/3
D. y = 5/12

B?

Answer 1

@jigglypuff314

Answer 2

The variable y is said to be inversely proportional to x if xy=k for some constant k. This is equivalently stated as "y varies indirectly with x."
so plug in the first two x and y values to find k
then plug in the second x and k to find the second y

Answer 3

Umm.. confused :/

Answer 4

find k when xy = k
(8)(6) = ?

Answer 5

then plug k into xy = k
and solve for y (10)y=(k)

Answer 6

48

Answer 7

\(\bf \begin{array}{llll}
\textit{something }&\textit{varies inversely to }&\textit{something else}\\ \quad \\
\textit{something }&=\cfrac{(\textit{some value })}{\textit{something else}}\\ \quad \\
y&=\cfrac{(n)}{x}
\end{array}\\ \quad \\
x=8\qquad y=6\\ \quad \\
\implies y=\cfrac{(n)}{x}\implies 6=\cfrac{n}{8}\)

find "n" first

Answer 8

once you find "n", plug it back in \(\bf y=\cfrac{(n)}{x}\) along with the given "x" value to find "y"

Answer 9

its A?

Answer 10

dunno... what did you get?

Answer 11

correct :)

Answer 12

you know.. I thought that was the answer the first time.. don't know what changed O.o

Answer 13

oh, and thanks :)

Answer 14

glad we could help :)

Answer 15

i gtg ttyl :)

Answer 16

ok, bye!