Determine the check digit for the Avis rental car with identification number 540047. (Se...

Determine the check digit for the Avis rental car with identification number 540047. (See Example 5.)

EXAMPLE 5 Airline companies, the United Parcel Service, and the rental-car companies Avis and National use the mod 7 values of identification numbers to assign check digits. Thus, the identification number 00121373147367 (see Figure 0.2) has the check digit 3 appended to it because 121373147367 mod 7 5 3. Similarly, the UPS pickup record number 768113999, shown in Figure 0.3, has the check digit 2 appended to it.