What is the probability of rolling a sum of either 7 or 11 when throwing two fair dice simultaneously?
Answer and explanation
Correct answer: A. 2 / 9
- Step 1: Outcomes with sum 7: (1,6), (2,5), (3,4), (4,3), (5,2), (6,1) [6 outcomes].
- Step 2: Outcomes with sum 11: (5,6), (6,5) [2 outcomes].
- Step 3: Total favorable = 6 + 2 = 8 out of 36 outcomes.
- Step 4: Probability = 8 / 36 = 2 / 9.
Practise more Quantitative Ability and Reasoning.
Free questions with an explanation for every one, and full timed CSS Pakistan mock tests.
More Quantitative Ability and Reasoning questions
- A civil services training cohort has 60 officers. 36 speak Pashto, 28 speak Balochi, and 12 speak neither language. How many officers speak…
- If 12 clerks can process 480 files in 8 days working 6 hours a day, how many clerks are needed to process 600 files in 5 days working 8 hour…
- A civil services candidate scores 68%, 74%, and 82% in three compulsory papers of 100 marks each. What minimum score must she obtain in the…
- Two cities Islamabad and Lahore are connected by a 375 km highway. Car A leaves Islamabad at 8:00 AM heading towards Lahore at 75 km/h. Car…
- In a provincial development fund, the allocation ratio between Health, Education, and Roads is 4:5:7. If the Roads allocation exceeds Health…
- What is the next term in the logical number sequence: 3, 7, 15, 31, 63, ...?