Answer: 0.205
Step-by-step explanation:
The probability in one flip is equal to 0.5.
Now, if we do 10 flips, we want 4 times that the coin ends in heads and the other 6 times it must end in tails, so the probability is:
0.5^4*0.5^6 = 0.5^10
Now, this is the case where in the first 4 flips we get heads and in the other 6 we get tails, but we have other ways to get only 4 heads (for example in the last 4 flips, 2 at the beginning and 2 at the end, etc)
So we also need to calculate all the possible permutations of 4 heads in 10 flips. this is:
C = 10!/(10 - 4)!*4! = (10*9*8*7)/(4*3*2*1) = 210
So the probability that we are looking for is:
P = (0.5^10)*210 = 0.205
