Answer:
Step-by-step explanation:
Definitions and concepts
The Poisson process is useful when we want to analyze the probability of ocurrence of an event in a time specified. The probability distribution for a random variable X following the Poisson distribution is given by:
And the parameter
represent the average ocurrence rate per unit of time
For this case we know that 
And we want the probability that during the next five minutes, three cars will arrive, so then our rate becomes:

And we want this probability:

And if we use the pmf we got:
Answer: 1
Step-by-step explanation:
Answer:
5 (for c only)
Step-by-step explanation:
for c:
1st cleaning company: 
2nd cleaning company: 
set up as a system of equations. for them to cancle out make the y of one equation negative. I'll be making the second one negative ( it doesn't matter though)
it will look like:


make the two equations on top of eachother and line the terms up. Then combine them. The variable "y" will cancle out and you'll be left with
then you will add 3x to both sides to get
then divide both sides by 3 to get 
if you plug in 5 for x into both of the original equations you will see that they will both make $100 in five hours. So you answer is 5
Answer:
96%
Step-by-step explanation:
assume the whole number is x
the first thing is decreasing by 20 %
x - 20%x = 80% x
then now the 80%x is the whole number
now It's the turn of increasing
80%x + 20% * (80% x) = 80%x + 16%x = 96% x
I hope this is hlepful to you !!!!
Feel free to ask me in the comments