Probability of no heads = (0.5)^5 = 0.03125Probability of at least one head = 1 - probability of no heads = 1 - 0.03125 = 0.96875
The probability of tossing two heads in two coins is 0.25.
the probability is 0.03125 or 3.123%
If they are fair coins, it is 1/16.
The conditional probability is 1/4.
The probability is 1/2^4 = 1/16
It is 3/4 or 0.75
The probability would be once in 128 attempts. You don't have to toss seven coins simultaneously. the 7 tosses just have to be independent of one another.
No matter how many coins are thrown, the possibility of having AT LEAST ONE 'head' is 50%. This changes if you specify the number of 'heads' that must be shown.