The slope of the line on the graph represents Pete's speed. That slope is 8 miles/hour.
Paul walks 2 miles in 0.4 hours, so walks at (2/0.4) miles/hour = 5 miles/hour.
a) Pete is moving at a greater rate.
b) At 8 miles per hour, it takes Pete (2 mi)/(8 mi/h) = 1/4 h = 15 minutes to get to school. If Pete leaves 5 minutes later than Paul, he will reach school 20 minutes after Paul starts, while Paul is still 4 minutes away from the school.
Yes, Pete will catch Paul before they get to school.