Let the number of boys be x, then numbers of girls =2x ∴x+2x=60; or 3x=60; or x=20 So numbers of boys =20 and numbers of girls =40 Numbers of student behind Kamal in rank =(60−17)=43 Numbers of girls ahead of Kamal in rank =9 ∴ Numbers of boys behind Kamal in rank =(43−31)=12