Let be "x" the total number of students in the 5th grade.
Let be "n" the number of students who do not wear glasses and "g" the number of students do that wear glasses.
Based on the information given in the exercise, you can set up the following System of equations:
Subsitute the value of "g" into the first equation:
Evaluating, you get that "n" is:
Then, "x" will be the sum obtained by adding "n" and "g". This is:
The answer is: 108 students.