Question 1 - Past Year MCQ - Chapter 15 Class 10 Probability (Term 1)
Last updated at Aug. 7, 2021 by Teachoo
Question 1
A box contains 90 discs, numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears a prime-number less than 23, is:
Question 1 A box contains 90 discs, numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears a prime-number less than 23, is: (a) 7/90 (b) 10/90 (c) 4/45 (d) 9/89 Total number of disks = 90
Prime number less than 23 are…
2, 3, 5, 7, 11, 13, 17, 19
Number of prime numbers less than 23 = 8
Thus,
P(getting a prime number less than 23)
= (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑟𝑖𝑚𝑒 𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑙𝑒𝑠𝑠 𝑡ℎ𝑎𝑛 23)/(𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟𝑠)
= 8/90
= 𝟒/𝟒𝟓
So, the correct answer is (C)
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.
