Andy School had 510 students and Tim School had 30% more students. When an equal number of students left each school, the ratio of the students in Tim School to that in Andy School became 2 : 1. How many students were there in both schools in the end?

	Andy School	Tim School	Difference
Before	510		153
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 Andy School and Tim School at first and in the end the same. 

Difference between the number of students in both schools at first
= 30% x 510
= ³⁰₁₀₀ x 510
= 153

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

1 u = 153

Total number of students in both schools in the end
= 2 u + 1 u
= 3 u
= 3 x 153
= 459

Answer(s): 459