Question

how to know whether it is a direct variation or Inverse variation

Answer 1

The SAT often asks questions about direct variation and inverse variation. These questions use wording like “…varies directly with…”, “…varies inversely with…”, “…is directly proportional to…” and “…is inversely proportional to…”

The formulas for direct and inverse variation are as follows.

Direct Variation

As one variable increases, the other variable increases proportionately.

\[ y=kx \]

Inverse Variation

As one variable increases, the other variable decreases proportionately.

\[ y=\frac{k}{x} \]

Here is a typical SAT variation problem.

Answer 2

it depends upon the question!