Answer:
6 liters
Step-by-step explanation:
Let x represent the amount of pure concentrate used to make the punch. Then the total amount of concentrate in the punch is ...
0.20·10 +1.00x = 0.50(10+x)
x +2 = 0.5x +5 . . . . . eliminate parentheses
0.5x = 3 . . . . . . . . . . .subtract 2+0.5x
x = 6 . . . . . . . . . . . . . multiply by 2
6 liters of pure concentrate must be added to make a 50% punch.
419.10>419.099 419.10 is greater than 419.009
180x28 is the sum of the interior angles in a <span>30- gon</span>
Answer:
The 99% confidence interval for the fraction of U.S. adult Twitter users who get some news on Twitter is between 49.34% and 60.66%, which means that we are 99% sure that the true percentage of US adult Twitter users who get some news is in this interval.
Step-by-step explanation:
Confidence interval:
A confidence interval has the following format:
In which M is the sample mean, z is related to the confidence level and s is the standard error.
55% of U.S. adult Twitter users get at least some news on Twitter (Pew, 2013). The standard error for this estimate was 2.2%.
This means that
99% confidence level
So , z is the value of Z that has a pvalue of , so .
Lower bound of the interval:
Upper bound:
The 99% confidence interval for the fraction of U.S. adult Twitter users who get some news on Twitter is between 49.34% and 60.66%, which means that we are 99% sure that the true percentage of US adult Twitter users who get some news is in this interval.