The ratio of the number of boys to the number of girls in Mr. Brown's class is 5:4. Which of the following can be calculated using the information given?

A. The number of girls in Mr. Brown's class
B. The number of boys in Mr. Brown's class
C. The ratio of the number of students in Mr. Brown's class to the number of students in the school
D. The ratio of the number of girls in the class to the number of students in the class

You've received several answers this evening. Now it's your turn.

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The correct answer is B. The number of boys in Mr. Brown's class can be calculated using the ratio given.

Using the given information that the ratio of boys to girls in Mr. Brown's class is 5:4, we can calculate the following:

A. The number of girls in Mr. Brown's class: To calculate the number of girls, we need to know the total number of students in the class. Since we only have a ratio and not the actual number of students, we cannot determine the exact number of girls.

B. The number of boys in Mr. Brown's class: Similar to calculating the number of girls, we cannot determine the exact number of boys without knowing the total number of students. Therefore, we cannot calculate the number of boys based on the given information.

C. The ratio of the number of students in Mr. Brown's class to the number of students in the school: This ratio cannot be calculated using the given information because we do not have any information about the total number of students in the school.

D. The ratio of the number of girls in the class to the number of students in the class: Since the ratio of boys to girls is given as 5:4, we can conclude that for every 4 parts representing girls, there are 5 parts representing boys. Therefore, the ratio of girls to students in the class is 4:9. This is the correct answer.

So, the correct answer is D. The ratio of the number of girls in the class to the number of students in the class.