The box plot below shows the number of years that 12 schools have participated in an interschool swimming meet:
a box and whisker plot is drawn using a number line from 0 to 10 with primary markings and labels at 0, 5, 10. in between two primary markings are 4 secondary markings. the box extends from 1 to 6 on the number line. there is a vertical line at 3.5. the whiskers end at 0 and 8. above the plot is written duration of participation. below the plot is written years.
at least how many schools have participated for more than 1 year and less than 3.5 years?
3
6
10
11