Answer:
The 85% confidence interval for the population proportion that claim to always buckle up is (0.7877, 0.8441).
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
.
They randomly survey 391 drivers and find that 319 claim to always buckle up.
This means that 
85% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 85% confidence interval for the population proportion that claim to always buckle up is (0.7877, 0.8441).
How much after subtraction
You try to find the opposite value and figure out if they add up the same
Answer:
<h3>
4.71 glasses </h3>
<u>Steps:</u>
Let say you can fill N no of 0.35 L glasses with 1.65 L.
<em><u>Then</u></em><em><u>,</u></em>
N times 0.35 =1.65
N × 0.35=1.65
N=1.65/0.35
N=4.71
It means you can fill 4 glasses completely and 71% of the 5th glass.
Assignment: 
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Answer: 
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Explanation: 
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[ Step One ] Divide Both Sides By 5

[ Step Two ] Simplify

[ Step Three ] Subtract 4 From Both Sides

[ Step Four ] Simplify

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