If 60% of the students at school are girls and the number of boys is 300, how many girls are at the school?
Boys make up 100% - 60% = 40% of the total number of students.
The total number of students at the school is 300 / (40/100) = <<300/(40/100)=750>>750 students.
Since 60% of the students are female, there are (60/100) * 750 = <<60/100*750=450>>450 female students.
#### 450