The number given in the question is in decimal form. It has to be first changed to fraction and then only can it be changed to a mixed fraction. The calculations have to be done correctly and then the problem is very straight forward.Now let us concentrate on the problem in hand.
Then
6.54 = 654/100
= 327/50
= 6 27/50
From the above deduction we can definitely conclude that the mixed number for 6.54 is 5 27/50. I hope this simple procedure will help you to attempt such type of problems in future without requiring any additional help.