Obviously, this 2-digit number is of the form N =x6, where x is the "tens" digit and 6 is the "ones" digit. Since "it gives a remainder of 5 when divided by 7", it means that N-5 is divisible by 7. N-5 is the number of the form x1 (referring to N = x6), i.e. N-5 is ended by "1". Among 2-digit numbers there are only TWO of the form x1 that are divisible by &. They are 21 and 91. 91 is the largest, and it produces N = 96.