It would be 16 more 6th graders that are not in either band or orchestra.
15 6th Graders in band
9 6th Graders in both classes
+18 6th Graders in orchestra
-----
42 6th Graders in either class
100 6th Graders in total
-42 6th Graders in either class
-------
58 6th Graders in neither class
58-42= 16 more 6th Graders that are not in either class
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Answer: 
Step-by-step explanation:
If you meant to solve for "z", then refer to the attachment below.
Answer:
The surrender of Detroit
Step-by-step explanation:
The other two were american victories, the surrender of Detroit was a Indian/British victory and an early one in the war
