Question

a cellphone is charging at a rate of 7% every minute and has 11% of its battery. a tablet is dying at a rate of 2% every minute and has 83% of its battery. after how many minutes will both devices have the same percent of battery? write the equation: m + = m + m =

Explanation:

Step1: Define the equations for battery levels

Let $m$ be the number of minutes. The cellphone's battery level is given by the equation $y_1 = 7m+ 11$ (7% increase per minute with an initial 11%). The tablet's battery - level is given by the equation $y_2=-2m + 83$ (2% decrease per minute with an initial 83%).

Step2: Set the two equations equal

We want to find when $y_1=y_2$, so we set up the equation $7m + 11=-2m+83$.

Step3: Solve for $m$

First, add $2m$ to both sides: $7m+2m + 11=-2m+2m + 83$, which simplifies to $9m+11 = 83$. Then subtract 11 from both sides: $9m+11 - 11=83 - 11$, giving $9m=72$. Finally, divide both sides by 9: $m=\frac{72}{9}=8$.

Answer:

Write the equation: $7m + 11=-2m+83$
$m = 8$