<image>The distribution of students in the four grades of Yingcai School is shown in the pie chart on the right. Based on a survey of the extracurricular reading habits of all the students during the summer vacation, the bar chart below shows the reading conditions of each grade. Given that there are a total of 1,500 students surveyed from the four grades of Yingcai School, then:
(1) How many extracurricular books did the first-year high school students read in total during the summer vacation?
(2) Which grade's students read the fewest extracurricular books during the summer vacation, and how many books did they read in total?
(3) How many extracurricular books did the students in all four grades of the school read on average per person during the summer vacation?