To predict the average final grade percentage using the given trend line equation \(y = -7.2x + 98.9\) for a student who spent 10 hours on social media (where \(x = 10\)), we can plug in the value of \(x\) into the equation:
\[ y = -7.2(10) + 98.9 \]
Calculating this:
\[ y = -72 + 98.9 \] \[ y = 26.9 \]
Rounding to the nearest whole number gives us \(27\).
Therefore, the correct response is:
The average final grade is 27% if a student spent 10 hours on social media.