thirty percent of all the students in a school are in a play. all students exept for 140 are in the play. how many students are in the school?

There is exactly 200 students in the school.
In order to find this, we know that 70% of students are not in the play (because 30% was in the play). Now, in order to solve for the total number, we can divide the students not in the play by the 70%.
140/.70 = 200 Students.