Currently, the equation is 60=8.50h+13.25 and h stands for the hours that Sammie worked. So, you need to solve for h by first subtracting 13.25 (his tips) and getting the amount that he received for the hours that he worked.
You should now have 46.75=8.50h
Our final step, is to divide 46.75 by 8.50 to get h by itself and determine the total hours that Sammie worked.
In the end, you should come out with h=5.5, which means that Sammie worked 5.5 hours.
5.5 hours because if you subtract the tips by the total you get 46.75. That is the amount he made without tips then you divide 46.75 by the hourly rate which is 8.5 and you get 5.5 hours