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Answer:
0.0021
Step-by-step explanation:
move decimal three to the left
<span>This would be a bell curve with a z-score of greater than +2.00, since 3 minutes is exactly two standard deviations greater than the mean of 2.00. Looking at a z-score table for the proportion of the curve that lies in the 1-tailed area greater than 2.00, we find that the value is .0228. This would be the probability that the conversation is over three minutes: 0.0228 or 2.28%.</span>
Answer:
Part A) The graph in the attached figure
Part B) 
Step-by-step explanation:
Let
y------> the price of gas
x-----> the volume of gas purchase
we know that
The relationship between the cost of gas and the volume purchase represent a direct variation and remember that a relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form 
In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin
In this problem the constant of proportionality k is equal to

and the y-intercept b is equal to zero because the line passes through the origin

therefore
the linear equation is


using a graphing tool
see the attached figure