Nick School had 325 pupils and Reggie School had 40% less pupils. When an equal number of pupils joined each school, the ratio of the pupils in Reggie School to that in Nick School became 5 : 4. How many pupils were there in both schools in the end?

	Nick School	Reggie School	Difference
Before	325		130
Change	+ ?	+ ?
After	5 u	4 u	1 u

Since an equal number of pupils joined each school, the difference in the number of pupils at first and in the end between the 2 schools remains the same.  Make the difference between the number of pupils in Nick School and Reggie School at first and in the end the same. 

Difference between the number of pupils in both schools at first
= 40% x 325
= ⁴⁰₁₀₀ x 325
= 130

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

1 u = 130

Total number of pupils in both schools in the end
= 5 u + 4 u
= 9 u
= 9 x 130
= 1170

Answer(s): 1170