Answer: The cost of one sandwich is $4.25 and the cost of one cup of coffee is $2.25.
Step-by-step explanation:
Let x be the cost of one sandwich and y be the cost of one cup of coffee.
By considering the given situation, we have the following equations :-

Multiply 2 on both sides of equation (2) , we get

Subtract equation (1) from equation (3), we get

Put value of y in (1), we get

Hence, the cost of one sandwich is $4.25 and the cost of one cup of coffee is $2.25.
Answer:
0.55% probability that exactly 5 out of the first 13 customers buy a magazine
Step-by-step explanation:
For each customer, there are only two possible outcomes. Either they buy a magazine, or they do not. The probability of a customer buying a magazine is independent of other customers. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
10% of his customers buy a magazine
This means that 
What is the probability that exactly 5 out of the first 13 customers buy a magazine?
This is P(X = 5) when n = 13. So


0.55% probability that exactly 5 out of the first 13 customers buy a magazine
Answer:
B
Step-by-step explanation:
5.8 multiplied by 3.1 equals 17.98, and you can round to 18 ounces.