In a class of 60, where the number of girls is twice the number of boys, Kamal is ranked 17th from the top. If there are 9 girls ahead of Kamal, how many boys are ranked after him?
12
Let the number of boys be x.
Then, the number of girls = 2x.
∴ x+2x = 60 or x = 20.
So, number of boys = 20, number of girls = 40.
Number of students behind Kamal in rank = 60 - 17 = 43
Number of girls ahead of Kamal in rank = 9
Number of girls behind Kamal in rank = 40 - 9 = 31
Hence number of boys behind Kamal in rank = 43 - 31 = 12