George School had 590 pupils and Zeph School had 30% less pupils. When an equal number of pupils joined each school, the ratio of the pupils in Zeph School to that in George School became 5 : 4. How many pupils were there in both schools in the end?

	George School	Zeph School	Difference
Before	590		177
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 George School and Zeph School at first and in the end the same. 

Difference between the number of pupils in both schools at first
= 30% x 590
= ³⁰₁₀₀ x 590
= 177

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

1 u = 177

Total number of pupils in both schools in the end
= 5 u + 4 u
= 9 u
= 9 x 177
= 1593

Answer(s): 1593