The coin is thrown 10 times. What is the probability that the coat of arms will be dropped 3 times?

The probabilities that the coat of arms will or will not fall out are equal to p = q = 0.5;
The probability that with 10 tosses the coat of arms will fall out 3 times using the Bernoulli formula:
P10 (3) = C (10.3) p ^ 3 q ^ 7;
C (10.3) = 10! / (3! (10 – 3)!) = 8 9 10 / (1 2 3) = 120;
P10 (3) = 120 0.5 ^ 3 0.5 ^ 7 = 0.1172.
Answer: 0.1172.