Find the average rate of change of g ( x ) = 5 x 3 + 4 from x = − 1 to x = 3

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school. each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220