A woman earns $ 1,350 in interest from two accounts in one year. If she has three times as much invested at 7% as she does at 6%
1 answer:
Answer:
The woman invested $15,000 at 7% interest rate and $5,000 at 6% interest rate.
Step-by-step explanation:
We are given the following in the question:
Let x be the interest earned from 7% interest rate and y be the interest earned from 6% interest rate.
The woman invested has three times as much invested at 7% as she does at 6%.
Thus, we can write the equation:
The total interest is $1,350.
Thus, we can write the equation:
Solving the two equations by substitution method:
Thus, she invested $15,000 at 7% interest rate and $5,000 at 6% interest rate.
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Let x be the number of times they raise the price on the newspaper. Then the new cost of the newspaper is
Let y be the newspaper they sell, then the income will be
Now, we know that the circulation is of 500, assuming that they sold every newspaper at the original price now the number the will sell will be
Plugging the value of y in the first expression we have that the income will be
Then the income is given by the function
To find the maximum value of this functions (thus the maximum income) we need to take the derivative of the function,
no we equate the derivative to zero and solve for x.
This means that we have an extreme value of the function when x=9. Now we need to find out if this value is a maximum or a minimum. To do this we need to take the second derivative of the function, then
Since the second derivative is negative in the point x=9, we conclude that this value is a maximum of the function.
With this we conclude that the number of times that they should raise the price to maximize the income is 9. This means that they will raise the price of the newspaper (9)($0.05)=$0.45.
Therefore the price to maximize the income is $0.35+$0.45=$0.80.
Answer:
<em>45 possible connections</em>
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Step-by-step explanation:
The general equation for finding the possible number of connections in a network is given as
where n is the number of computers on the network.
for 4 computers, we'll have
=
= 6
for 5 computers, we'll have
=
= 10.
therefore, for 10 computers, we will have
=
= <em>45 possible connections</em>