If the number is x then x/8=a+5/8, where a is a whole number. So x=8a+5 and x-5=8a. Therefore 8 must go into x-5, and x-5 must be 5 (a=0), 13 (a=1), 21 (a=2), 29 and so on. There is no number in the range bigger than 5 and less than 13 is 13, which is what the question is asking for, so there is no solution. If the question had said less than or equal to 13, then the answer would have been x=13.