Answer:
And we can find this probability using the complement rule and the normal standard table or excel:
The firgure attached illustrate the problem
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the retirement savings of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the complement rule and the normal standard table or excel:
The firgure attached illustrate the problem
Step-by-step explanation:
I don't know if the first set of numbers is all in one set, but I'll do my best to give you an answer.
Really all you need to do is use PEMDAS for the first question.
(Parentheses, exponents, multiply, divide, add, subtract. In that order)

Then to simplify that fraction next to it, notice that 0.018 is 3x 0.06.
that's a 3:1 ratio, so it ends up simplifying to this:

Lastly, to solve the division of that fraction. If you divide by a fraction, you multiply whatever it's dividing by its inverse.
So...
