60 percent of the students in a marching band are girls. There are 30 girls in the marching band. How many students are there altogether?

Answer 1

60/100 = 30/x

60x = 3000

60x/60 = 3000/60

x = 50

There are 50 students.

Answer 2

Let n = total number of students.
It was said that 60% of n are girls, which is according to the problem, equal to 30. Thus,
60% * n = 30
Note that 60% is also equal to 0.6 in decimal form:
0.6 * n = 30
n = 30/0.6
n = 50 students

Hope this helps :3