Brain Teasers & Mental Math
Clock angle: how many degrees does the hour hand move in one minute, and how many times per day are the hands exactly overlapping?
Model answer
Hour hand: 0.5° per minute (30° per hour ÷ 60).
Overlaps per day: 22 times. The hands coincide every 12/11 hours ≈ 65.45 minutes, not every 60. In 12 hours they overlap 11 times (the minute hand…
The full, human-reviewed answer is in the bank.
Sign up free and Daily 10 serves you 10 questions a day from all 2,300+ — or go Pro for unlimited reps.
Pro unlocks every model answer — $19.99/mo.
More from Brain Teasers & Mental Math
- You roll one fair six-sided die. What is the probability you roll a number greater than 4?
- Flip a fair coin twice. What is the probability of getting at least one head?
- Draw one card from a standard 52-card deck. What is the probability it is a face card (J, Q, or K)?
- Draw one card from a 52-card deck. What is the probability it is a heart OR a king?
- Roll two fair dice. What is the probability the two dice show the same number (a double)?
- A test for a disease is 99% accurate (99% sensitivity and 99% specificity). The disease affects 1 in 10,000 people. You test positive. What is the probability you actually have it?
Try the real thing
1 / 3M&A & Merger Models
What makes an acquisition accretive or dilutive to EPS?
Superday coming up? Take the cheat sheet.
The technicals and stories to have cold before you walk in — free, one email, no mailing list.
Free tier: 20 cards + 10 daily reps + ALL drills — no credit card required.