MANCHESTER, Mo. (KMOV.com) -- A local high school student scored a 36 on the ACT -- the highest marks possible on the exam.Leela Chapman, a junior at Parkway South, took the ACT with other juniors in late April. She learned recently that she aced the the exam.According to the school, more than 1.6 million students took the admissions and placement exam in 2012. Just one-tenth of one percent of students who take the exam earn a perfect score.The ACT tests students on English, math, reading and science, with each test scored on a scale of 1-36. A student's composite score is the average of their marks in the four subjects.