In a class same number of boys and girls. if 5/6 of girls and 1/8 of boys are honour students. what part of class consists of girls who are not honour students?

5/6 of girls and ⅛ of boys are honour studens. Then 1/6 of girls are not honour. And as there is the same number of boys and girls in the class, then not honour girls take 1/6 girls' number and half of that number from all class: 1/6 * ½ = 1/12.

The proportion of girls who are not honour students is given by:
1 - 5/6 = 1/6.
However girls are 1/2 of the class. Therefore the part of the class which is girls who are not honour students is given by:
1/6 * 1/2 = 1/12