When a question is asking you for the y-intercept based on a graph, all you have to do is look to see at what point does the function cross/intersect the y-axis. The x-value will always be zero in a y-intercept. By looking at the graph you see that the function crosses the y-axis at the point (0, -1), which is your answer.
Well if it was 8 hours in the morning and 7 in the evening per day of the week it would be 105 divided by 2 for the number of sessions would equal to 52.5 sessions. if it was just that amount of time from that whole week, it would be 15 hours divided by 2 which would give you 7.5... Did that help?
