Answer:
3x=78+x-2
Step-by-step explanation:
Square roots and squares cancel eachother. therefore the problem is simply:
2.35 + -4.27= -1.92
-- Look for a common factor of both the top and bottom numbers.
==> 5 is a common factor of 45 and 100 .
-- Divide the top and bottom numbers by their common factor.
==> 45/100 = 9/20 .
-- Look for another common factor of both the top and bottom numbers.
==> The only common factor now is ' 1 ' .
==> That means the fraction is now as simplified as it can get.
Answer:
We need a sample size of at least 383.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error is:

85% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 85% confidence level with an error of at most 0.03
We need a sample size of at least n.
n is found with 
Then






Rounding up
We need a sample size of at least 383.
There are two separate equations for this question that use the same variable.
Mary took 7 hours to complete a trip with traffic. This would use the following expression:

Mary took 4 hours to complete the same trip without traffic. The average rate of speed was 27 mph faster than the trip with traffic. This uses the following expression:

Both trips had the same distance. From the information provided, we can set up the following equation:

x represents the average rate of speed on both trips.
Distribute 4 to each term in parentheses:



Subtract 4x from both sides:

Divide both sides by 3 to get x by itself:

The average speed for the slower trip is 36 mph.
We can plug this value into the first equation:

Mary lives
252 miles away from the mountains.