Answer:
length of rectangle = 5
width of rectangle = 5
Area of rectangle = 25
Step-by-step explanation:
Since the length of the rectangle is "x", and the value of the area is given by the product of the length "x" times the width "10-x", indeed, the area "y" of the rectangle is given by the equation:
Now, they tell us that the area of the rectangle is such that coincides with the maximum (vertex) of the parabola this quadratic expression represents. So in order to find the dimensions of the rectangle and therefore its area, we find the x-coordinate for the vertex, and from it, the y-coordinate of the vertex, which is the rectangle's actual area.
Recall that the formula for the x of the vertex of a quadratic of the form :
is given by the formula:
which in our case gives:
Therefore, the length of the rectangle is 5, and its width (10-x) is also 5.
The area of the rectangle is therefore the product of these two values: 5 * 5 = 25
Which should coincide with the value we obtain when we replace x by 5 in the area formula:
Answer:
b) The width of the confidence interval becomes narrower when the sample mean increases.
Step-by-step explanation:
The confidence interval can be calculated as:
a) The width of the confidence interval becomes wider as the confidence level increases.
The above statement is true as the confidence level increases the width increases as the absolute value of test statistic increases.
b) The width of the confidence interval becomes narrower when the sample mean increases.
The above statement is false. As the sample mean increases the width of the confidence interval increases.
c) The width of the confidence interval becomes narrower when the sample size n increases.
The above statement is true as the sample size increases the standard error decreases and the confidence interval become narrower.
Use PEMDAS
Parentheses
Exponents
Multiply
Divide
Add
Subtract
Answer: 6 hours
Step-by-step explanation: If you write an equation for this scenario it would be y = 12+3x. 12 is the starting value and x represents how many hours the bike is rented, therefore 3 dollars would be added to the initial 12 each hour. So if Lucy spent $30 then it would change to 30= 12+3x. Now you essentially just need to work backwards. Rearrange the equation and move 12 to the left of the equal sign to make 30-12=3x. Combine vairable to make 18=3x. Divide 3x by 3 to isolate x and divide 18 by 3 as well to make it even. This looks like 18/3=3x/3. Meaning it would end up as 6=x.
