Question

If y varies inversely as x squaredand y = 6 when x = 30, what is y when x = 6?

Answer 1

y = 150

Explanation:

Given that y varies inversely as x² then the equation relating them is

y =
`(k)/(x^2)` ← k is the constant of variation

To find k use the condition y = 6 when x = 30 , then

6 =
`(k)/(30^2)` =
`(k)/(900)` ( multiply both sides by 900 )

5400 = k

y =
`(5400)/(x^2)` ← equation of variation

When x = 6 , then

y =
`(5400)/(6^2)` =
`(5400)/(36)` = 150