Answer:
There will be 800 hundred pounds.
Explanation:
First 4 hrs doubles do goes up to 100.
After 4 more hours, 100 doubles so now we are at 200.
After 4 more hours, 200 doubles so now we are at 400
After 4 more hours, 400 doubles so now we are at 800.
Alll 12 hrs have gone by and we are at 800.