<h2>
Answer:</h2>
The probability that exactly one customer dines on the first floor is:
0.26337
<h2>
Step-by-step explanation:</h2>
We need to use the binomial theorem to find the probability.
The probability of k success in n experiments is given by:

where p is the probability of success.
Here p=1/3
( It represents the probability of choosing first floor)
k=1 ( since only one customer has to chose first floor)
n=6 since there are a total of 6 customers.
This means that:

The gcf of 18 and 20 is 2, so your answer is:
2(9+10)
Answer:
Step-by-step explanation:
Figure it out yourself