Hint:
1. probability of 3-5 heads, plus
2. probability of 2 heads and 0-1 tails, plus
3. probability of 1 head and 0 tails.
Hint:
1. probability of 3-5 heads, plus
2. probability of 2 heads and 0-1 tails, plus
3. probability of 1 head and 0 tails.