Answer:
75
Step-by-step explanation:
By "composite" we mean "numbers that can be factored further."
The numbers between 10 and 20 but not including 10 or 20 are:
12, 14, 15, 16, 18
12, 14, 15, 16 and 18 are all composite numbers (all can be factored).
Their sum is 75.
