2 out of 6
In a large enough number of tosses, it is a certainty (probability = 1). In only the first three tosses, it is (0.5)3 = 0.125
The probability is 1 out of 5
The probability is 0, since there will be some 3-tosses in which you get 0, 1 or 3 heads. So not all 3-tosses will give 2 heads.
1/4
It is 3/8.
In a large enough number of tosses, it is a certainty (probability = 1). In only the first three tosses, it is (0.5)3 = 0.125
The probability of two tails on two tosses of a coin is 0.52, or 0.25.
The probability is 1/4
The probability is 0.0322
The probability is 1 out of 5
0.5
If the coin is fair, the probability of getting all heads will decrease exponentially towards 0.
The probability is 0, since there will be some 3-tosses in which you get 0, 1 or 3 heads. So not all 3-tosses will give 2 heads.
1/4
In a single toss? zero. In two tosses, well that's a different question. Possible combinations are TT, HT, TH and HH, of which 2 of the 4 are one head and one tail. So probability is 0.50 in two tosses.
33%
It is 3/8.