Mark School had 635 pupils and Zane School had 40% more pupils. When an equal number of pupils left each school, the ratio of the pupils in Zane School to that in Mark School became 2 : 1. How many pupils were there in both schools in the end?

	Mark School	Zane School	Difference
Before	635		254
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 Mark School and Zane School at first and in the end the same. 

Difference between the number of pupils in both schools at first
= 40% x 635
= ⁴⁰₁₀₀ x 635
= 254

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

1 u = 254

Total number of pupils in both schools in the end
= 2 u + 1 u
= 3 u
= 3 x 254
= 762

Answer(s): 762