12km is the answer hope this heps
The question is a little vague but I believe the answer would be 16. 16 divided in half is 8. And that is 8 less than 16. < Not the answer for this question.
I didn't understand the question until Maria answered, she is completely right! Sorry for the misunderstanding.
the answer is x= 4
AB and CD are the same length
8x-1 =31
8x=32
x=4
Your answer would be 3160.
