Question

In the graph, the battery percentage is decreasing at the rate of _______ % per hour.

• A. $-2.5$
• B. $-5$
• C. $2.5$
• D. $5$

Answer 1

The correct option is A $-2.5$

Consider the points $(1,-2.5)$ and $(2,-5)$ on the line.
You know,
$Unitrate=Slope=\frac{Rise}{Run}$
$=\frac{Changeiny}{Changeinx}$
$=\frac{-5-(-2.5)}{2-1}$
$=\frac{-5+2.5}{2-1}$
$=\frac{-2.5}{1}$
$=-2.5$

$\therefore Unitrate=-2.5$

As the unit rate is negaitive, the graph is decreasing.

So, the battery percentage is decreasing at a rate of $-2.5\%$ per hour.