How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters? We want 95% confidence that the sample mean is within 5 minutes of the population mean, and the population standard deviation is known to be 7 minutes.

25 computers will be selected

Step-by-step explanation:

Where: Z -value at 95% confidence = 1.96; SD = Standard deviation = 10 minutes; N = Sample size; Margin error = 4 minutesSubstituting;4 = 1.96*10/Sqrt (N)Sqrt (N) = (1.96*10)/4 = 4.9N = 4.9^2 = 24.01 ≈ 25

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is