Question 18 - CBSE Class 12 Sample Paper for 2026 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Transcript

Question 18 A person observed the first 4 digits of your 6-digit PIN. What is the probability that the person can guess your PIN? (A) 1/81 (B) 1/100 (C) 1/90 (D) 1Our 6-digit PIN would look like Of which, the person knows first 4 digits Now, there is only 1 correct pin ∴ Number of correct PIN = 1 And, the person can put any digit from 0 to 9 in the last two positions So, there are 10 options for one position Now, Total Number of ways of putting last 2 digits = 10 × 10 = 100 Thus, Required Probability = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑤𝑎𝑦𝑠 ℎ𝑒 𝑐𝑎𝑛 𝑝𝑢𝑡 𝑐𝑜𝑟𝑟𝑒𝑐𝑡 𝑃𝐼𝑁)/(𝑇𝑜𝑡𝑎𝑙 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑤𝑎𝑦𝑠 𝑓𝑜𝑟 𝑝𝑢𝑡𝑡𝑖𝑛𝑔 𝑙𝑎𝑠𝑡 2 𝑑𝑖𝑔𝑖𝑡𝑠) = 𝟏/𝟏𝟎𝟎 So, the correct answer is (B)