There are 40 musicians that are only marching band.
Step-by-step explanation:
Since we knot that there are 25 musicians that do both that means there is 60 - 25 = 35 musicians who do only jazz band. From his we can answer the question because....
100 = a + b + c
Where "a" is the number of musicians who go only to jazz, "b" is the number of people who do both, and "c" is the number of people that go only to the marching band. From here we can do this....
