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:
Scalene acute triangle
Step-by-step explanation:
And acute has less than 90 degrees all of them are less than 90 which makes it acute, scalene
Answer: The equation is W^2 + 4W - 96= 0
{Please note that ^2 means raised to the power of 2}
Step-by-step explanation: We have been given hints as to the measurement of the length and width of the rectangle. The length is given as four more than the width. What that means is that whatever is the width, we simply add four to get the measurement of the length. Therefore if the width is W, then the length is W + 4.
That is,
L = W + 4 and
W = W
Also we have the area given as 96.
Remember that the area of a rectangle is given as
Area = L x W.
In this question, the Area is expressed as
Area = (W + 4) x W
96 = W^2 + 4W
Subtract 96 from both sides of the equation and we have
W^2 + 4W - 96 = 0.
We now have a quadratic equation from which we can determine the dimensions of the rectangle
The output k at input t = -7 is -89
Step-by-step explanation:
In order to find the value of a expression on given number, we put the number in given expression in place of independent variable
So,
Given expression is:

It is given that the value of t has to be -7
so putting t=-7 in the expression

Hence,
The output k at input t = -7 is -89
Keywords: Expressions, input, output
Learn more about expressions at:
#LearnwithBrainly
Answer:
You gotta deserve it
Step-by-step explanation: