Question

The function f(x) varies inversely with x and f(x) = 6 when x = 4.

What is f(x) when x = 8?



A.24


B.3


C.12


D.10

Answer 1

The answer would be 12 because when we do 6/4=1.5
So then to get f(x)
We have to take 8•1.5=12

Answer 2

3

Explanation:

given f(x) varies inversely with x then the equation connecting them is

f(x) =
`(k)/(x)` ← k is the constant of variation

to find k use the given condition f(x) = 6 when x = 4, then

k = xf(x) = 4 × 6 = 24, hence

f(x) =
`(24)/(x)` ← variation equation

when x = 8, then

f(x) =
`(24)/(8)` = 3