Seth School had 500 students and Daniel School had 40% less students. When an equal number of students joined each school, the ratio of the students in Daniel School to that in Seth School became 5 : 4. How many students were there in both schools in the end?

	Seth School	Daniel School	Difference
Before	500		200
Change	+ ?	+ ?
After	5 u	4 u	1 u

Since an equal number of students joined 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 Seth School and Daniel School at first and in the end the same. 

Difference between the number of students in both schools at first
= 40% x 500
= ⁴⁰₁₀₀ x 500
= 200

Difference between the number of students in both schools in the end
= 5 u - 4 u
= 1 u

1 u = 200

Total number of students in both schools in the end
= 5 u + 4 u
= 9 u
= 9 x 200
= 1800

Answer(s): 1800