Answer:

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

And replacing we got:


We can find the probability of interest using the normal standard table and with the following difference:

Step-by-step explanation:
Let X the random variable who represent the expense and we assume the following parameters:

And for this case we want to find the percent of his expense between 38.6 and 57.8 so we want this probability:

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

And replacing we got:


We can find the probability of interest using the normal standard table and with the following difference:

Answer:

And we can find the individual probabilities like this:
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".
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:
Solution to the problem
For this case we want to find this probability:

And we can find the individual probabilities like this:
And adding we got:

one hundred thirty two million, eight hundred eighty thousand and sixteen
(Your commas are in the incorrect spot)
fifteen thousand, eight hundred and two
You’d plug in the 0.6 for x. so you’d multiple 0.6 times 2.5 then you’d get 1.5 then you’d add 1.5 plus 5.8 and get 7.3
Answer: 37 + 19 = 56
Step-by-step explanation: easy all you need to do is take away nineteen from 56 then you get m