Question

If y varies inversely as (x-3). If y = 5 when x =7 find y when x=5

Answer 1

Given that y varies inversely as (x-3) .When y is 5 x is 7 . We need to find out the value of y when x is 5 .

• According to the Question ,

$\sf\longrightarrow y \propto \dfrac{1}{x-3}\\\\\sf\longrightarrow y =\dfrac{k}{x-3}$

• where k is a constant .

And ,

$\sf\longrightarrow 5 =\dfrac{k}{7}$

$\sf\longrightarrow k = 7*5$

$\bf\longrightarrow k = 35$

Now , when x is 5 ,

$\sf\longrightarrow y = \dfrac{k}{x-3}$

$\sf\longrightarrow y =\dfrac{35}{5-3}$

$\sf\longrightarrow y=\dfrac{35}{2}$

$\sf\longrightarrow \boxed{\red{\sf y = 17.5 }}$