Answer:
a) Positive linear
b) 72
c) Marks scored when no time is spend on homework.
Explanation:
a) relationship between the hours spent on homework and the test scores
As the time spent on homework increases the test score increases.
Similarly if less time is spent on homework, there would be a decrease in test score.
The two variables are directly related.
Thus, there relationship can be expressed as a positive linear relationship.
b) The model function

where y is the test score and x is the time spent on homework in hours.
Score predicted by model when x = 4

Thus, model predict that the score on test will be 72 when 4 hours are spent on homework.
c) Interpretation of 40
When x = 0

Interpretation:
Thus, when Paul spends no time on homework that is zero hours are spend on homework, then, Paul will score 40 on test.