If the values in the table below model a proportional relationship, what is the equation for the function?

Given:

The table represents a proportional relationship.

To find:

The equation of the function.

Solution:

If y is directly proportional to x, then

    ...(i)

where, k is the constant of proportionality.

From the given table it is clear that the function passes through (2,1). So, the equation must be satisfied by the point (2,1).

Putting x=2 and y=1 in (i), we get

Putting , we get

Therefore, the correct option is A.