Tag Difficulty – Easy

Easy brain teasers and puzzles

Mystery Killer Riddle

A detective is called upon to solve the riddle of the mystery killer in a high-profile murder.

There are only three suspects:

  • Aaron, the best friend
  • Patty, the gardener
  • Jason, the neighbor

The victim was holding a calendar, and it seems he marked several of dates before he passed away: the second of January, the sixth of February, the third of April, the fourth of October, and the first of November.

With this information, the detective identified the culprit. Who was it?

Continue reading “Mystery Killer Riddle”

Favorite Fruit and Favorite Color

Ava, Beth, Cam, and Derek each have a different favorite fruit and favorite color. We know their favorite fruits are apple, banana, cherry, and durian, and their favorite colors are blue, green, red, and yellow. We also know:

  1. Cam does not like apples or cherries
  2. Derek’s favorite color is yellow and his favorite fruit is not banana
  3. The person whose favorite fruit is cherry also likes the color green
  4. Beth’s favorite color is red and her favorite fruit is not apple
  5. The person whose favorite fruit is durian does not like the color blue

What is each person’s favorite fruit and favorite color?

Continue reading “Favorite Fruit and Favorite Color”

Reroll the Die

Suppose there is a game in which you roll a fair, 6-sided die and win dollars equal to the outcome of the roll. How much would you expect to win on average?

Suppose, if you don’t like the outcome of the roll, you can reroll the die once, and win dollars equal to the outcome of the 2nd roll (once you choose to reroll, you can no longer go back to the 1st roll). How much would you expect to win on average?

Suppose, if you don’t like the outcome of the 2nd roll, you can reroll the die once more, and win dollars equal to the outcome of the 3rd roll (once you choose to reroll, you can no longer go back to previous rolls). How much would you expect to win on average?


This was an actual brain teaser question once asked at Jane Street for an interview for an intern role.

Continue reading “Reroll the Die”