Daniel School had 680 students and Will School had 20% more students. When an equal number of students left each school, the ratio of the students in Will School to that in Daniel School became 2 : 1. How many students were there in both schools in the end?

	Daniel School	Will School	Difference
Before	680		136
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 Daniel School and Will School at first and in the end the same. 

Difference between the number of students in both schools at first
= 20% x 680
= ²⁰₁₀₀ x 680
= 136

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

1 u = 136

Total number of students in both schools in the end
= 2 u + 1 u
= 3 u
= 3 x 136
= 408

Answer(s): 408