Question

What is the relation between time and number of items sold in the given graph?

• A. $y=x$
• B. $y=10x$
• C. $y=1000x$
• D. $y=100x$

Answer 1

The correct option is C $y=1000x$

A proportional relationship between input (x) and output (y) can be represented by the equation y = mx

$\text{Where, "m"}=\text{rate of change}=\frac{y}{x}$

Here, "y" is number of items sold and "x" is time.


Choose a point, let say (2,2).
Here, the number of items sold is in thousands.
So, value of y will be 2 × 1000 = 2000.

$\therefore \text{Slope, m}=\frac{y}{x}=\frac{2000}{2}=1000$

So, the equation for the proportional relationship for the graph is
$y=1000x$.