Books are identified by an international standard book number (isbn), a 10-digit code x1x2…x10, assigned by the publisher. these 10 digits consist of blocks identifying the language, the publisher, the number assigned to the book by its publishing company, and finally, a 1-digit check digit that is either a digit or the letter x (used to represent 10). this check digit is selected so that ∑10i=1ixi≡0 mod 11 and is used to detect errors in individual digits and transposition of digits. (a) the isbn for a book is 1−69−632945−q where q is the check digit. what is q?