Answer:
Step-by-step explanation:
x = number of rows
780=x(x+4)


there are 26 rows and 30 students in each row 26*30=780
Answer:
3 hours of tv per day
Step-by-step explanation:
there are 7 days in a week
21/7 = 3
1. Page 1-9 (1digit/page
x 9page) = 9 digits = 9 page
2. Page 10-99 (2digits/page x 90page)= 180 digits = 90 page
3. Page 100-999 (3digits/page x 900page)= 2700 digits = 900
page
2,929 total digits – (9 digits + 180 digits + 2700 digits)= 40
digits
Since there are only 4 digits after page 999 we divide 40/4
= 10, thus there are 10 more pages after 999
So the book has 1009 pages.
Hope
this answer will be a good help for you.
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Answer:
The 90% confidence interval using Student's t-distribution is (9.22, 11.61).
Step-by-step explanation:
Since we know the sample is not big enough to use a z-distribution, we use student's t-distribution instead.
The formula to calculate the confidence interval is given by:
Where:
is the sample's mean,
is t-score with n-1 degrees of freedom,
is the standard error,
is the sample's size.
This part of the equation is called margin of error:
We know that:
degrees of freedom
Replacing in the formula with the corresponding values we obtain the confidence interval:
