There are total 77 students in the sixth grade.
Given, there are 28 students that have braces.
out of which there are 4 students with braces for every 7 students.
Therefore, 4 ₊ 7 = 11, which means every 11 member has 4 members with braces.
Therefore, based on the given conditions, formulate:
28 × (4 ₊ 7) ÷ 4
28 × 11 / 4
now cross out the common factors.
7 × ( 11)
multiply the above terms.
77
hence we get the answer as 77 students in total in the class.
Learn more about Simplification here:'
brainly.com/question/723406
#SPJ9