A school has five houses A,B,C,D and E. A class has 23 students, 4 from house A, 8 from house B, 5 from house C, 2 from house D and rest from house E. A single student is selected at random to be the class monitor. The probability that the selected student is not from A, B and C is
Total number of students = 23
Number of students in house A, B and C = 4 + 8 + 5 = 17
∴ Remains students = 23 - 17 = 6
So, probability that the selected student is not from A, B and C = 6/23