The average height of a group of boys was 123 centremetre. After one girl whose height was 137centremetre joined the group, the average height of the group became 125 centremetre. Find the number of boys in the group.

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