Max had $20 more in school bucks than Rylee. Rylee had $15 more than Brock. Altogether they had $455. Create a tape diagram an e
1 answer:
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Answer:
18 L
Step-by-step explanation:
Given : she must mix a solution of 67% herbicide with a solution of 46% herbicide to form 42 liters of a 55% solution.
To Find: How much of the 67% solution must she use?
Let x = amount of 67% solution needed
Then 42-x=amount of 46% solution needed
Now we know that the pure herbicide in the 67% solution
So, pure herbicide = (0.67x)
The amount of pure herbicide in the 46% solution (0.46(42-x))
Now 42 liters of a 55% solution = (0.46(42-x))
So,
Amount of 67% solution + Amount of 46% solution = 42 liters of a 55% solution
⇒0.67x+0.46(42-x)=0.55*42
⇒0.67x+19.32-0.46x=23.1
⇒0.21x=3.78
⇒
⇒x = 18 liters
Hence she use 18 liters of the 67% solution
Answer:
The margin of error of u is of 3.8.
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 28 - 1 = 27
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 27 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.7707
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The margin of error of u is of 3.8.
The lower end of the interval is the sample mean subtracted by M. So it is 31.2 - 3.8 = 27.4 minutes
The upper end of the interval is the sample mean added to M. So it is 31.2 + 3.8 = 35 minutes
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.