Answer: 6 girls do not wear spectacles.
Explanation: 3/4 of 40 students are boys => 3/4 x 40 = 30. Therefore, there are 30 boys in the class.
Number of girls = 40 - 30= 10
2/5 of 10 girls wear spectacles => 2/5 x 10 =4
Therefore number of girls that do not wear spectacles is 10 - 4= 6girls
