Answer:
4.6 hours
Step-by-step explanation:
Let 'S' be the number of study hours, 'C' be the number of class attendance hours and 'G' be his prior GPA. His new GPA is given by:
[tex]GPA = 0.5S+0.25C+0.25G[/tex]
For C = 4 hours and G = 2.75, the number of study hours required to reach a GPA of 4.0 is:
[tex]4.0 = 0.5S+0.25*4+0.25*2.75\\S=\frac{4.0-1-0.6875}{0.5} \\S=4.6\ hours[/tex]
Sam needs to study 4.6 hours in order to get a 4.0 GPA.