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Quiz & insight
This quiz is about careful conclusions as well as knowledge. Each question has three possible answers. The explanation is part of the experience: a lucky guess and sound reasoning may earn the same points, but the explanation shows why the answer works.
Play immediately as a guest. A name is only needed to save scores.
How it works
Choose one answer. Once submitted, that question is graded and your choice cannot be changed. You see your selected letter, the correct letter and an explanation. Then choose Continue. At the end you see your number of correct answers and what the result means for your score.
Worked example
A box holds 2 green and 8 yellow cards. Drawing one blindly gives a 2/10 = 20% chance of green. If you then want another green without replacement, the second probability is 1/9. Whether you replace a card changes the calculation.
A useful approach
Read even the answers that initially seem unlikely. The difference between “some” and “all” may decide the question. Hard includes conditional probabilities and combinations. Working on paper is fine; there is no time limit rewarding rushed answers.