Show that there are transpositions of two digits that are not detected by an ISBN-13.A routing transit number (RTN) is a bank code used in the United States which appears on the bottom of checks. The most common form of an RTN has nine digits, where the last digit is a check digit. If d1d2…d9 is a valid RoTN. the congruence 3(d1 + d4 + d7) +7(d2 + d5 + d8) + (d3 + d6 + d9) = 0 (mod 10) must hold.

Solution:Step 1:In this problem, we have to show that there are transpositions of two digits that are not detected by an ISBN-13