Harrison Elementary School is overcrowded with 1590 students, so 40% of the students are going to move to a new school. There are 3 grade levels, and each grade level needs one 20-person advanced class and the rest of the students divided evenly into 6 additional classes. How many students will there be in each normal class at the new school?
Please reason step by step, and put your final answer within \boxed{}.
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