Question

The function f(x) varies inversely with x and f(x) = 4 when x = 12.

what is f(x) when x = 3?

A. 1
B. 9
C. 16
D. 19

Answer 1

c

Explanation:

Answer 2

Answer: C. 16.

Explanation:

We are given inverse relation between f(x) and x.

The function f(x) varies inversely with x.

Inverse relation could be written as

f(x) =
`(k)/(x)`.

We also given f(x) = 4 when x = 12.

Plugging f(x) = 4 and x=12 in the above inverse relation to get the value of constant k.

`4=(k)/(12)`.

On cross multiplying, we get

12× 4 =
`12 * (k)/(12)`

48 = k

Now, we need to find f(x) for x=3.

Plugging k=48 and x=3 in inverse relation, we get

`f(x) = (48)/(3) = 16`.

Therefore, f(x)=16 when x=3.