Answer:
A. (4x + 9) (4x − 9) is the correct answer.
The answer is most likly to be B.
<span>Total mass of mixture is given as 5/6 pound, in which 1/4 pound is gravel. Amount of sand in the mixture will be 5/6 - 1/4 = 7/12
So, the ratio of sand to that of gravel in given mixture is 7/12:1/4 = 7:3. i.e every 10
parts of mixture contain 7 parts of sand and 3 parts of gravel.
If we are given 1-pound of same mixture, it will contain 1 * 3/10 pound gravel, i.e. 0.3 pound.</span>
Answer:
We see that the p value is lower than the significance level given of 0.01 so then we can conclude that the true mean for the nicotine content is significantly higher than 40 mg
Step-by-step explanation:
Information provided
represent the average nicotine content
represent the sample standard deviation
sample size
represent the value to check
represent the significance level for the hypothesis test.
t would represent the statistic
represent the p value for the test
System of hypothesis
We want to verify if the nicotine content of the cigarettes exceeds 40 mg , the system of hypothesis are:
Null hypothesis:
Alternative hypothesis:
The statistic for this case would be:
(1)
And replcing we got:
The degrees of freedom are:
The p value would be:
We see that the p value is lower than the significance level given of 0.01 so then we can conclude that the true mean for the nicotine content is significantly higher than 40 mg