Answer:
a)
b)
And adding we got:

Step-by-step explanation:
Previous concepts
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
Solution to the problem
Let X the random variable of interest, on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
Part a
For this case we want this probability

And using the pmf we got:
Part b
And adding we got:

Answer:
there arent any choices-
Step-by-step explanation:
Answer:
300x
Step-by-step explanation:
alll you have to do is multipy 15 and 20 and you will get 300
after that just add the x to the end
The probability of tossing a coin of getting head is 1/2 because there are two faces in the coin one of them is head
P(h) = 1/2
Since there are two coins will tossing together, then the probability of each coin getting a head is 1/2
We need to getting head in both, then we will multiply the two of them

Then the probability is 1/4