Daniel School had 620 pupils and Tommy School had 40% more pupils. When an equal number of pupils left each school, the ratio of the pupils in Tommy School to that in Daniel School became 2 : 1. How many pupils were there in both schools in the end?

	Daniel School	Tommy School	Difference
Before	620		248
Change	- ?	- ?
After	2 u	1 u	1 u

Since an equal number of pupils left 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 Daniel School and Tommy School at first and in the end the same. 

Difference between the number of pupils in both schools at first
= 40% x 620
= ⁴⁰₁₀₀ x 620
= 248

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

1 u = 248

Total number of pupils in both schools in the end
= 2 u + 1 u
= 3 u
= 3 x 248
= 744

Answer(s): 744