In: Advanced Math
The United States Postal Service (USPS) uses 11-digit serial numbers on its money orders. The first ten digits identify the document, and the last digit is the check digit. The check digit is obtained by a11 = a1 + · · · + a10 (mod 9). For example, one of the money order has serial number 16094004377. (a) The first ten digits of the serial number on a USPS money order are 7306125986. Find the last digit (the check digit). (b) Will this scheme detect all single-digit errors? Prove your statement. (c) Will this scheme detect all transposition error? Why?