The distribution of passenger vehicle speeds traveling on a certain freeway in california is nearly normal with a mean of 73.7 miles/hour and a standard deviation of 4.77 miles/hour. (a) what percent of passenger vehicles travel slower than 80 miles/hour? (round your answer to two decimal places.) % (b) what percent of passenger vehicles travel between 60 and 80 miles/hour? (round your answer to two decimal places.) % (c) how fast do the fastest 5% of passenger vehicles travel? (round your answer to four decimal places.) mph (d) the speed limit on this stretch of the freeway is 70 miles/hour. approximate what percentage of the passenger vehicles travel above the speed limit on this stretch of the freeway. (round your answer to two decimal places.)

A) 90.32%

B) 90.11%

C) 81.546 miles per hour

D)77.93%

Step-by-step explanation:

Given data:

speed  = 73.7 miles/hour

standard deviation = 4.77 miles /hour

a)

                   = P (z< 1.31)

                   = 0.90320  = 90.32%

b)

                   = P (-2.872< z< 1.31)

                   = P (z<1.31) - P(z<-2.87)

                   = 0.90320 - 0.00205

                   = 0.90115  = 90.11%

c) P(X <X) = 0.95

    z = 1.645

x = 81.546  miles per hour

                   = P (z> -0.775)

                   = 0. 0.7793  = 77.93%

use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you