Hard Riddles

Hard Math and Logic

5 bandits split 100 coins. Senior proposal?

Hard Math and Logic

Families stop childbearing after 1st boy. Sex ratio?

Hard Math and Logic

4 people: 1, 2, 5, 10 mins. Bridge (max 2). Min time?

Hard Math and Logic

3 doors: Heaven, 1-day Hell, 2-day Hell. Avg days?

Hard Math and Logic

110m rope. 1ft slack added/pulled up. Truck fits?

Hard Math and Logic

Which is greater: e? or ?e?

Hard Math and Logic

Surgeon with 2 gloves must operate on 3 patients. How?

Hard Math and Logic

Duck in pond. Cat runs 4x faster on edge. Escape?

Hard Math and Logic

1/4 into tunnel. Meet train at start or end. Speed ratio?

Hard Math and Logic

Sum of digits from 1 to 1,000,000?

Hard Math and Logic

Helium balloon in car accelerating forward. Direction?

Hard Math and Logic

100 ants on 1m stick at 1cm/s. Max time to clear?

Hard Math and Logic

Shortest distance from room corner to opposite corner?

Hard Math and Logic

3-way. Accuracy 33/50/100. You (33) go first. Action?

Hard Math and Logic

Alex (RR/BB wins). Sam (BR/RB wins). Better position?

Hard Math and Logic

7-part bar. Pay 1 part/day for 7 days. Snap twice?

Hard Math and Logic

3R, 2B hats. 1st/2nd can't guess. What is 3rd's color?

Hard Math and Logic

6 chambers, 2 consecutive bullets. Fired empty. Spin or stay?

Hard Math and Logic

Times digit "3" is printed between 3,000 and 4,000?

Hard Math and Logic

54 cards (2 Jokers). Probability both are Jokers?

Hard Math and Logic

1/1000 trick coin. Flip 10 heads. Prob it's the trick coin?

Hard Math and Logic

100B and 100W pearls. Maximize chance of picking Black.

Hard Math and Logic

Two 1-hr ropes, burn inconsistently. Measure 45 mins?

Hard Math and Logic

Black win $1, Red lose $1. Quit anytime. Strategy?

Showing 505 to 528 of 569 results

5 bandits split 100 coins. Senior proposal?

Families stop childbearing after 1st boy. Sex ratio?

4 people: 1, 2, 5, 10 mins. Bridge (max 2). Min time?

3 doors: Heaven, 1-day Hell, 2-day Hell. Avg days?

110m rope. 1ft slack added/pulled up. Truck fits?

Which is greater: e? or ?e?

Surgeon with 2 gloves must operate on 3 patients. How?

Duck in pond. Cat runs 4x faster on edge. Escape?

1/4 into tunnel. Meet train at start or end. Speed ratio?

Sum of digits from 1 to 1,000,000?

Helium balloon in car accelerating forward. Direction?

100 ants on 1m stick at 1cm/s. Max time to clear?

Shortest distance from room corner to opposite corner?

3-way. Accuracy 33/50/100. You (33) go first. Action?

Alex (RR/BB wins). Sam (BR/RB wins). Better position?

7-part bar. Pay 1 part/day for 7 days. Snap twice?

3R, 2B hats. 1st/2nd can't guess. What is 3rd's color?

6 chambers, 2 consecutive bullets. Fired empty. Spin or stay?

Times digit "3" is printed between 3,000 and 4,000?

54 cards (2 Jokers). Probability both are Jokers?

1/1000 trick coin. Flip 10 heads. Prob it's the trick coin?

100B and 100W pearls. Maximize chance of picking Black.

Two 1-hr ropes, burn inconsistently. Measure 45 mins?

Black win $1, Red lose $1. Quit anytime. Strategy?

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