Answer:
There are 20 students who have red hair in a school of 100 students.
Step-by-step explanation:
First, make a simplified ratio. To make a simplified ratio, you have to divide the given ration by the greatest common factor, in this case 4. 20 divided by 4 is 5 and 4 divided by 4 is 1 so the simplified ratio is 1 red-haired student to 5 students. Next, you have to divide the whole number of students in the school by 5, because the biggest number in the simplified ratio is 5. 100 divided by 5 is 20 so 20 is your answer.
