Answer:

And we can find this probability using the normal standard table or excel and we got:

The figure shows the calculation for this case.
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 hardness 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 normal standard table or excel and we got:

The figure shows the calculation for this case.
Answer: B
Step-by-step explanation:
Answer:
en cada vaso debe verter 237 mililitros
Step-by-step explanation:
1896 Divídelo en 8 es igual que 237 por 8
Answer:
Step-by-step explanation:
Sale price = original price - discount
discount = 44% of original price = 44% of $37 = 0.44 x 37 = $16.28
Sale price = $37 - $16.28 = $20.72