Answer:
3 days: 8 heads.
10 days: 1024 heads.
Step-by-step explanation:
If each time the hero cuts off all the heads, then the amount doubles each time. This can also be represented using powers of 2, with 2^n, where n is the number of days.
2^1 = 2, so two heads the first time he cuts it.
2^2 = 4, so four heads the second time he cuts it.
With three, 2^3 is 8 so there are 8 heads.
With ten, 2^10 is 1024 so there are 1024 heads.
