To predict the number of minutes of exercising Sam will do if she spends 30 minutes watching television, we can use the given function [tex]\( y = -0.78x + 95 \)[/tex], where [tex]\( x \)[/tex] represents the number of minutes of television watched and [tex]\( y \)[/tex] represents the number of minutes spent exercising.
Given:
[tex]\( x = 30 \)[/tex]
1. Substitute [tex]\( x = 30 \)[/tex] into the function:
[tex]\[
y = -0.78(30) + 95
\][/tex]
2. Calculate the product [tex]\(-0.78 \times 30\)[/tex]:
[tex]\[
-0.78 \times 30 = -23.4
\][/tex]
3. Add this result to 95:
[tex]\[
y = -23.4 + 95
\][/tex]
[tex]\[
y = 71.6
\][/tex]
From these steps, the predicted number of minutes Sam will spend exercising when she watches 30 minutes of television is 71.6 minutes.
Thus, the best prediction from the given options is approximately 72 minutes.
