The function f (x) varies inversely with x and f (x) = 0.2 when x = 0.4.

what is f (x) when x = 1.6

Varies inversely:

f (x) = k/x

There is always a constant of variation, k to solve for using the given information. when x = 0.4; f (x) = 0.2

0.2 = k/0.4

0.2 (0.4) = k

0.08 = k

final equation : f (x) = 0.08/x

when x = 1.6

f (x) = 0.08/1.6

f (x) = 0.05