Answer:
0.6472 = 64.72% probability that a randomly selected page does not need to be retyped.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:
In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given interval.
Poisson distribution with an average of three errors per page
This means that 
What is the probability that a randomly selected page does not need to be retyped?
Probability of at most 3 errors, so:

In which
Then

0.6472 = 64.72% probability that a randomly selected page does not need to be retyped.
Hello there, this problem is just basic addition, here is what it would look like

Solve it and we get 78.21
Your income is the money you receive or acquire it's the inflow and your total expenses are the money you spent it's the outflow
This is what i got when i worked it out
15.4m Square because That is what I got when I times those two together