There are $100+80-60=120$ females in either band or orchestra, so there are $230-120=110$ males in either band or orchestra.  Suppose $x$ males are in both band and orchestra.
\[80+100-x=110\Rightarrow x=70.\]
Thus, the number of males in band but not orchestra is $80-70=10\rightarrow \boxed{\text{A}}$.
PIE
The Pythagoras High School band has $100$ female and $80$ male members.  The Pythagoras High School orchestra has $80$ female and $100$ male members.  There are $60$ females who are members in both band and orchestra.  Altogether, there are $230$ students who are in either band or orchestra or both.  The number of males in the band who are NOT in the orchestra is
$\text{(A)}\ 10 \qquad \text{(B)}\ 20 \qquad \text{(C)}\ 30 \qquad \text{(D)}\ 50 \qquad \text{(E)}\ 70$