In a class of 60 students where girls are twice that of boys, Laxmi ranked 27th from the top. If there are 9 boys ahead of Laxmi, how many girls are after her rank ?

Given number of girls are twice that of boys.

--> G=2B and G+B = 60 

Therefore,  G=40 and B= 20

Given Laxmi ranked 27th from the top and 9 boys are ahead of Laxmi.

Therefore, There are 17 girls ahead of Laxmi. 

Therefore, Number of girls who ranked after Laxmi = 40 - (17+1) = 22.