Final answer:
Kevin is incorrect because the ratio of girls to boys is 3:5. To get 8 students, the ratio would need to be 1:1. The actual number of students must be a multiple of the total parts of the ratio, which is 8 in this case.
Step-by-step explanation:
Kevin is incorrect about there being 8 students in the classroom based on the ratio of girls to boys being 3:5. A ratio of 3:5 means that for every 3 girls, there are 5 boys. Since ratios represent parts of a whole, the numbers 3 and 5 must be scaled by the same amount to find the actual number of girls and boys. When we add the parts of the ratio together (3 girls + 5 boys = 8 parts), we see this forms the total parts of the whole. Therefore, the minimum number of students this ratio could represent is 8. Yet, the number of students must be a multiple of this sum. For Kevin's assumption of 8 students to be correct, the ratio would have to be 1:1, but it isn't. To get 8 students, the ratio would have to be scaled by 1, which would give us 3 girls and 5 boys - a total of only 8 students, not 8 each. Therefore, there must be a multiple of 8 students in the classroom. Examples of correct total student numbers include 16, 24, 32, etc., because these numbers are multiples of 8.