47. Only tenth-, eleventh-, and twelfth-grade students
attend Washington High School. The ratio of tenth
graders to the school’s total student population is
86:255, and the ratio of eleventh graders to the
school’s total student population is 18:51. If 1 student
is chosen at random from the entire school, which
grade is that student most likely to be in?
D. All grades are equally likely.
E. Cannot be determined from the given information