Answer:
The American population was 20% of the British population.
Step-by-step explanation:
Let us call 
the american population, 
the British population before the migration, and 
the population that migrated from America to Britannia.
Now, the population that migrated was 20% of the american population:
,
and the same population increase the British population by 4%:
Combining equation (1) and (2) we get:
Thus, the American population was 20% of the British population.
What triangle? Is there one on here?
So 4X6=24 so i think the answer is 24
