Out of the 25 students in Mrs. Coulter's class, 15 are girls. In the school there are 390 boys. If the ratio of boys to students
in Mrs. Coulter's class is proportional to the ratio of the number of boys in the school to the total number of students in the school, how many students are at the school?
This is a dense question. Let's look at it piece by piece:
1. The ratio of boys to students in the class is 10/25. If there are 25 students and 15 girls, that leaves 10 boys.
2. The question says that the ratio is in proportion of boys to total students in the school. "In proportion" in this case means that if we convert 10/25 to a fraction with numerator 390, the denominator is the amount of students in school.
3. 10x39=390. What you do the numerator you must do to the denominator: 25x39=975.
