Answer:
- She traveled 45 miles in 1 hour
- She traveled 270 miles in 6 hours
- She traveled 360 miles in 8 hours
Step-by-step explanation:
If Mrs. Anglin traveled at a speed of 90 miles in 2 hours, it means that her speed per hour is:
= 90/2
= 45 mph
If she is travelling at 45mph then in 1 hoour she would have traveled 45 miles.
In 6 hours she would have traveled:
= 45 * 6
= 270 miles
In 8 hours she would have traveled:
= 45 * 8
= 360 miles
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The appropriate choice appears to be ...
B. -3/5
Answer:
35.9 grams
Step-by-step explanation:
We use the formula:

Where
q is heat released
m is mass
C_p is the constant 2.44
ΔT is change in temperature
We put the info in the formula and solve for m (mass):

The mass of ethanol is 35.9 grams
Answer:
n=206
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that
, we can use as prior estimate of p 0.5, since we don't have any other info provided, and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
And replacing into equation (b) the values from part a we got:
And rounded up we have that n=206