If a certain coin is flipped, the probability that the coin will land heads is 1/2. If the coin is flipped 5 times, what is the probability that it will land heads up on the first 3 flips and not on the last 2 flips?
the probability of the first 3 flips which is heads up is (1/2)^3
and the probability of the first 3 flips which is not heads up is (1/2)^2
multiple them together,
btw, if we want the side of n times of coin flipp to be what we wanted to be, then the probability is (1/2)^n