Conditional probability by counting outcomes in the reduced sample space
This type of question, asked 3 times: May 2021 S1, 25 Apr 2025 S1, 15 May 2026 S1. All 3 questions below, oldest first.
Try each one first, then open its answer.
Question 1
May 2021 S1
112Out of 50 tickets numbered 00, 01, 02, \ldots, 49, one ticket is drawn randomly. The probability of the ticket having the product of its digits 7, given that the sum of the digits is 8, isTap an option to check your answer.
Question 2
25 Apr 2025 S1
139A family has 3 children. The probability that all the three children are girls, given that at least one of them is a girl isTap an option to check your answer.
Question 3
15 May 2026 S1
100Two fair dice are tossed simultaneously. Let be the event that the sum of the numbers is prime, and be the event that at least one die shows a number 5. The odds against the occurrence of event given that event has already occurred is:Tap an option to check your answer.