Justin School had 400 students and Michael School had 30% more students. When an equal number of students left each school, the ratio of the students in Michael School to that in Justin School became 2 : 1. How many students were there in both schools in the end?

	Justin School	Michael School	Difference
Before	400		120
Change	- ?	- ?
After	2 u	1 u	1 u

Since an equal number of students left each school, the difference in the number of students at first and in the end between the 2 schools remains the same.  Make the difference between the number of students in Justin School and Michael School at first and in the end the same. 

Difference between the number of students in both schools at first
= 30% x 400
= ³⁰₁₀₀ x 400
= 120

Difference between the number of students in both schools in the end
= 2 u - 1 u
= 1 u

1 u = 120

Total number of students in both schools in the end
= 2 u + 1 u
= 3 u
= 3 x 120
= 360

Answer(s): 360