Suppose you buy a new car whose advertised mileage is 23 miles per gallon (mpg). After driving your car for several months, yo
u find that its mileage is 19.4 mpg. You telephone the manufacturer and learn that the standard deviation of gas mileages for all cars of the model you bought is 1.07 mpg. A. Find the z-score for the gas mileage of your car, assuming the advertised claim is correct.
B. Does it appear that your car is getting unusually low gasmileage?
We have a work problem here. We can use our knowledge on ratio and proportion in order to set up and equation to determine what is being asked. We do as follows:
1 job / 3 hours for both = 1 job / 8 hours for charlie + 1 / x hours for sam alone