Question

There are 200 more teachers in School X than in School Y. After 25% of the teachers left School X and 50% of teachers left School Y, the number of teachers who remained in School X is thrice that of the number of teachers in School Y. Find the number of teachers in School X at first

Answer 1

There are 200 more teachers in School X than in School Y --->
number of teachers in Y ---- x
number of teachers in X ---- x+200

After the exodus:
1/4 of teachers in X left, leaving (3/4)(x+200)
1/2 of teachers in Y left, leaving (1/2)x

the number of teachers who remained in School X is thrice that of the number of teachers in School Y ---->
(3/4)(x+200) = 3(1/2)x
times 4
3(x+200) = 6x
x = 200

School X originally had 400 teachers, school Y had 200