Tommy School had 715 pupils and Ken School had 40% less pupils. When an equal number of pupils joined each school, the ratio of the pupils in Ken School to that in Tommy School became 3 : 2. How many pupils were there in both schools in the end?

	Tommy School	Ken School	Difference
Before	715		286
Change	+ ?	+ ?
After	3 u	2 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 Tommy School and Ken School at first and in the end the same. 

Difference between the number of pupils in both schools at first
= 40% x 715
= ⁴⁰₁₀₀ x 715
= 286

Difference between the number of pupils in both schools in the end
= 3 u - 2 u
= 1 u

1 u = 286

Total number of pupils in both schools in the end
= 3 u + 2 u
= 5 u
= 5 x 286
= 1430

Answer(s): 1430