A school has 60% girls and 40% boys. If 20% of the girls wear glasses and 40% of the boys wear glasses, what percent of all students wears glasses?

Determine the percentage of girls wear glasses compared to all students.

g = 20% * 60%

g = 20/100 * 60/100

g = 1,200/10,000

g = 12/100

g = 12%

Determine the percentage of boys wear glasses compared to all students.

b = 40% * 40%

b = 40/100 * 40/100

b = 1,600/10,000

b = 16/100

b = 16%

Calculate the percentage of students wear glasses

s = 12% + 16%

s = 28%

The students wear glasses is 28%