9514 1404 393
Answer:
2.8¢, true
Step-by-step explanation:
The value of copper in a penny is reportedly about ...
(0.95 × 3.11 g)×(1 oz)/(28.35 g)×($0.27/oz) ≈ $0.028
Today, the value of the copper in a pre-1982 penny is about 2.8¢, more than double the value of the penny as legal tender.
The claim is true.
Answer:
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".
Let X the random variable that represent interest on this case, and for this case we know the distribution for X is given by:
And let represent the sample mean, the distribution for the sample mean is given by:
On this case
Solution to the problem
We want this probability:
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:
Answer:
1) (2.2, -1.4)
2) (1.33, 1)
Step-by-step explanation:
Question 1)
Two lines, with their corresponding equations are given and we have to find the solution to the system of equations.
The given lines are:
Equation of Line 1:
This line passes through the points: (0, 2.5) , (2.2, -1.4)
Equation of Line 2:
This line passes through the points (0, -3) , (2.2, -1.4)
By looking at the graph/given data we have to find the solution of these linear equations.
Remember that the solution of linear equations is an ordered pair, through which both the lines pass i.e. the point at which both the given lines intersect is the solution of the linear equations.
From the given data we can see that both the lines pass through one common point, (2.2, -1.4). Since, both lines pass through this point, this means this is the point of intersection of the lines and hence there solution.
So, the answer to this questions is (2.2, -1.4)
Question 2)
The given equations are:
y = 1.5x - 1 Equation 1
y = 1 Equation 2
We can solve these equations by method of substitution.
Substituting the value of y from Equation 2, in Equation 1, we get:
1 = 1.5x - 1
1 + 1 = 1.5x
2 = 1.5x
x = 2/1.5
x = 1.33
y = 1
Thus, the solution of the given linear equations is (1.33, 1)