Question

use for questions 7-9: mischa recorded the battery life of her laptop each hour after unplugging it.

battery life (%%)

1. find the rate of change after the first two hours of use after unplugging her laptop.

1. find the rate of change from two hours of use to two hours and 30 minutes of use.

1. find the rate of change from three hours and 30 minutes of use to five hours of use.

Explanation:

Step1: Extract Q7 data points

At 0 hours: 90%, at 2 hours: 70%

Step2: Calculate Q7 rate of change

$\text{Rate} = \frac{70 - 90}{2 - 0} = \frac{-20}{2} = -10$ % per hour

Step3: Extract Q8 data points

At 2 hours: 70%, at 2.5 hours: 60%

Step4: Calculate Q8 rate of change

$\text{Rate} = \frac{60 - 70}{2.5 - 2} = \frac{-10}{0.5} = -20$ % per hour

Step5: Extract Q9 data points

At 3 hours: 50%, at 5 hours: 10%

Step6: Calculate Q9 rate of change

$\text{Rate} = \frac{10 - 50}{5 - 3} = \frac{-40}{2} = -20$ % per hour

Answer:

1. -10 percent per hour
2. -20 percent per hour
3. -20 percent per hour