Cognitive Reflection Test Cognitive Reflection Reflective Reasoning Under Uncertainty 2 — Questions and Answers
Question 1: A man buys a horse for $60, sells it for $70, buys it back for $80, and sells it again for $90. What is his profit?
- $10
- $20 (Correct answer)
- $30
- $0
Correct answer: $20
He makes $10 profit on the first transaction and $10 on the second, for a total profit of $20.
Question 2: A clock shows 3:15. What is the angle between the hour and minute hands?
- 0 degrees
- 7.5 degrees (Correct answer)
- 15 degrees
- 22.5 degrees
Correct answer: 7.5 degrees
At 3:15 the minute hand is at 90°; the hour hand has moved 7.5° past 90° (15 min × 0.5°/min), so the angle is 7.5°.
Question 3: If you double a paper 42 times, approximately how thick is it compared to the distance from Earth to the Moon?
- Much thinner
- About the same
- Much thicker (Correct answer)
- Exactly the same
Correct answer: Much thicker
Doubling paper 42 times yields 2^42 × 0.1mm ≈ 440,000 km, which is thicker than the ~384,400 km Earth-Moon distance.
Question 4: What is the next number in the sequence: 2, 6, 12, 20, 30, __?
- 40
- 42 (Correct answer)
- 44
- 36
Correct answer: 42
The differences are 4, 6, 8, 10, 12 — so the next number is 30 + 12 = 42.
Question 5: A father is 4 times as old as his son. In 20 years, he will be twice as old. How old is the son now?
- 5 years old
- 10 years old (Correct answer)
- 15 years old
- 20 years old
Correct answer: 10 years old
Let son = x; father = 4x. In 20 years: 4x+20 = 2(x+20) → 4x+20 = 2x+40 → x = 10.
Question 6: You have 8 identical-looking balls but one is slightly heavier. Using a balance scale, what is the minimum number of weighings guaranteed to find the heavy ball?
- 1 weighing
- 2 weighings (Correct answer)
- 3 weighings
- 4 weighings
Correct answer: 2 weighings
Divide into groups of 3, 3, and 2; one weighing identifies which group has the heavy ball, and one more finds it: 2 weighings total.
Cognitive Reflection Test Cognitive Reflection Reflective Reasoning Under Uncertainty 2
A man buys a horse for $60, sells it for $70, buys it back for $80, and sells it again for $90.
What is his profit?