No. of boys=1100 No. of girls=900. 50% of boys= 50/100 * 1100=550 40% of girls=40/100 * 900= 360. therefore out of 2000 students (550+360) passed the exam therefore out of 2000, 910 students passed. now, Percent of candidates failed= 2000-910/2000 *100 (1090/2000) * 100 = 109/2 = 54.5%