A Web music store offers two versions of a popular song. The size of the standard Version is 2.9 megabytes (MB). The size of the high-quality version is 4.3 MB. Yesterday, there were 1220 downloads of the song for a total download size of 4070 MB. How many downloads of the high-quality version were there?

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

or