Travis scored points
Let's call the number of points scored in the first game A and the number of points scored in the second game B:
A = 18
since he scored 18 points in the first
B = A -3 = 18 - 3 = 15
B = 15
since he scored 3 fewer point in the second
The total number of point is
A + B = 18 + 15 = 33