A library contains 2000 books. There are 3 times as man non fiction books. Write and solve a systems of equations to determine t
1 answer:
Answer:
The number of fiction books is <u>500</u> and non fiction books is <u>1500</u>.
Step-by-step explanation:
Given:
Total book library contains = 2000.
There are 3 times as many non fiction books as fiction books.
Now, to determine the number of non fiction books and fiction books.
Let the fiction books be
And the non fiction books be
Total books = 2000.
Now, to get the number of non fiction books and fiction books we put an equation:
Dividing both sides by 4 we get:
Fiction books = 500.
Non fiction books =
Therefore, the number of fiction books is 500 and non fiction books is 1500.
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Answer:
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution 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 = 9 - 1 = 8
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 8 degrees of freedom(y-axis) and a confidence level of . So we have T = 1.8595
The margin of error is:
M = T*s = 1.8595*2.7 = 5
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 25.3 - 5 = 20.3 milligrams
The upper end of the interval is the sample mean added to M. So it is 25.3 + 5 = 30.3 milligrams.
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.
The principal amount is
<u>SOLUTION: </u>
Given that, simple interest ;
after 3 years
We have to find the principal.
Now, let the principal amount be p.
Then,
Now, we know that, Balance = Principal amount + Simple Interest