Answer:
33
Explanation:
To find the number of students, we must find out how many parts of a ratio are there.
7+4 = 11 parts
Then after finding the total parts, we know that the number of students must be a multiple of the total number of parts.
11 x 3 = 33
So, the total number of students is 33.
4 x 3 = 12 Boys
7 x 3 = 21 Girls.
Thank you.