Solution 1:
Bob can easily decode the message by following 3 simple steps:
1)First find the inverse of the matrix 2)Multiply the code with the inverted matrix by taking 3 numbers at a time. 3)Lastly, to get the decrypted message convert each number to its coresponding alphabetic character.
Solution 2:
May be. She has got the required information to find the inverse matrix,ie the message and the decrypted output.
Solution 3: