Answer:
Step-by-step explanation:
Divide each term by - 1/4 first
- -1/2x ÷ (- 1/4) = 1/2x × 4 = 2x
- -5/4y ÷ (- 1/4) = 5/4y × 4 = 5y
Now facor out - 1/4
- - 1/2x - 5/4y =
- - 1/4 (2x + 5y)
Answer:
$0.60
Step-by-step explanation:
The mean is the average. We add up all the numbers and divide by the number of numbers.
The total for 1st week is $12.48+$9.50+$10.25+$4.99+$8.59 = $45.81
Now, the mean:
Mean = 45.81/5 = $9.162
2nd week's total is 3 more than last week's total, so 2nd week's total is:
45.81 + 3 = $48.81
Now, Mean:
Mean = 48.81/5 = $9.762
The increase is 9.762 - 9.162 = $0.60
Answer:
C(x) = 25 + 2x
Step-by-step explanation:
He already has 25 cards.
He is collecting 2 cards per month. In x months, he will have collected:
2 * x = 2x cards
That means that the number of cards he will have after x months will be the sum of the cards he already has and the cards he collects per month:
C(x) = 25 + 2x
Answer:
n=1849
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
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 population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
Assuming that the proportion is estimated
. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=1849
X=14
2x=28
4x-9=47
you solve for x after you add all the sides