The probability is 0.25.
Look at it this way--if you toss a coin twice, there are four equally-probable outcomes:
So the probability of heads twice in a row is one in four, or 25%.
the chance of tossing heads is 1/2 (50%) The chance of tossing the next heads is 1/2 (50%) 1/2 x 1/2 = 1/4 (25%)
1/2 x 1/2 = 1/4
What is the chance of it landing on heads twice in a row?
75%
It is 0.25
If the coin is not biased, the answer is 0.375
The answer depends on how many times the coin is tossed. The probability is zero if the coin is tossed only once! Making some assumptions and rewording your question as "If I toss a fair coin twice, what is the probability it comes up heads both times" then the probability of it being heads on any given toss is 0.5, and the probability of it being heads on both tosses is 0.5 x 0.5 = 0.25. If you toss it three times and want to know what the probability of it being heads exactly twice is, then the calculation is more complicated, but it comes out to 0.375.
2:3...
1/2 x 1/2 = 1/4
It is 1/4.
The probability to get heads once is 1/2 as the coin is fair The probability to get heads twice is 1/2x1/2 The probability to get heads three times is 1/2x1/2x1/2 The probability to get tails once is 1/2 The probability to get tails 5 times is (1/2)5 So the probability to get 3 heads when the coin is tossed 8 times is (1/2)3(1/2)5=(1/2)8 = 1/256 If you read carefully you'll understand that 3 heads and 5 tails has the same probability than any other outcome = 1/256 As the coin is fair, each side has the same probability to appear So the probability to get 3 heads and 5 tails is the same as getting for instance 8 heads or 8 tails or 1 tails and 7 heads, and so on
Every time a coin is tossed there is a 50 / 50 chances of it coming up heads. There is no rule that says tossing it 100 or 6 times will change this.
What is the chance of it landing on heads twice in a row?
25%
75%
It is 0.25
If the coin is not biased, the answer is 0.375
The probability to get tails once is 1/2 (for a fair coin) The probability to get tails twice = the probability to get it once x the probability to get it a second time The probability to get tails 4 times in a row is (1/2)4=1/16 The probability to get tails n times in a row is (1/2)n=1/2n The same thing is also true for heads (same probability: 1/2 each time)