The following table indicates the mode of transportation to work for a random sample of 80 working mothers in Duluth, Minnesota.

Model of Transportation . . . . . . . . . . . . . Number of Mothers

Car . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Bike . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

If this sample is representative of all working mothers in Duluth, determine the probability that exactly three of five working mothers selected at random

(a) Take a car to work. 

(b) Take a bus to work.

Round answers to the nearest ten-thousandths where appropriate.