Question 18 - NCERT Exemplar - MCQ - Chapter 15 Class 10 Probability (Term 1)

Last updated at Oct. 27, 2021 by

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

Question 18
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
(A) 4/23 (B) 6/23 (C) 8/23 (D) 17/23
Now,
Number of students in A = 4
Number of students in B = 8
Number of students in C = 5
Number of students in D = 2
Number of students in E = 23 − (4 + 8 + 5 + 2) = 4
Now,
Probability that the selected student is not from A, B and C
= P(student is from D and E)
= (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑠𝑡𝑢𝑑𝑒𝑛𝑡𝑠 𝑖𝑛 𝐷 𝑎𝑛𝑑 𝐸)/(𝑇𝑜𝑡𝑎𝑙 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑆𝑡𝑢𝑑𝑒𝑛𝑡𝑠)
= (2 + 4)/23
= 𝟔/𝟐𝟑
So, the correct answer is (B)

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.