Answer:
The probability that more than half of them have Type A blood in the sample of 8 randomly chosen donors is P(X>4)=0.1738.
Step-by-step explanation:
This can be modeled as a binomial random variable with n=8 and p=0.4.
The probability that k individuals in the sample have Type A blood can be calculated as:

Then, we can calculate the probability that more than 8/2=4 have Type A blood as:

The answer is 10. If you replace the number letters with the numbers you get 6 + 10 / 2 - 1. Then you follow PEMDAS, so first divide 10 with 2 to get five (6 + 5 - 1). Add 6 and 5 to get 11 and subtract 1 to get the final answer of 10.