It’s -5, always look at your rise and run, they will help!
Answer:
(a) 
(b) 
(c) At 4 weeks, when both will be seeing an average of 3 hours of TV.
Step-by-step explanation:
a) For the students, they start at X(0)=5 h and ΔX=-0.5 h/week.
We can write

b) For the professors, they start at X(0)=1 h and ΔX=+0.5 h/week.
We can write

c) The seew which they will be watching the same amount of hours will be the 4th week.

The amount of hours will be

probabiltity is
outcome/total possible outcomes
hence probability is 1/6×10= 1/60
What do you need help with exactly ?