Suppose the board of directors for Cosmic Coffee wants to know the price range for the lowest 40% of drink sales. Find the z-score associated with the upper boundary of this price range.

Step-by-step explanation:

The z-score associated with the upper boundary of of this price range is -0.25.

Step-by-step explanation:

It is provided that the board of directors for Cosmic Coffee wants to know the price range for the lowest 40% of drink sales.

If X represents the price range of drink sales, then

P (X < x) = 0.40

Consider that X follows a Normal distribution.

To compute the probability of a normally distributed random variable we need to first convert the raw score to the z-scores.

The formula to z-score is:

Then,

P (X < x) = 0.40

⇒ P (Z < z) = 0.40

The value of z for this probability is:

z = -0.25

*Use a z-table.

Thus, the z-score associated with the upper boundary of of this price range is -0.25.

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m