You have 8 balls numbered 1, 3, 5, 7, 9, 11, 13 and 15. Select 3 balls and put them into the circles such that the sum of the numbers on them add up to 30.
Hard Riddles
4 Days for School
A student has missed an excessive number of days at school and thus the principal called him to his office and requested for an explanation.
The student said, “There just isn’t enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that’s 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school.”
The principal is confused, but can’t figure out why. What is wrong with the student’s argument?
Riddle AnswerThe Proposal
Unlike Joe, I was lying when I denied arguing against scrapping the proposal. Was Joe in favor of or against the proposal?
Riddle AnswerStolen Apple
During lunch hour, a group of boys from Mr. Bryant’s homeroom visited a nearby grocery store. One of the five stole an apple.
When questioned:
Jim said: “It was Hank or Tom.”
Hank said, “Neither Eddie nor I did it.”
Tom said, “Both of you are lying.”
Don said, “No, one of them is lying, the other is speaking the truth.”
Eddie said, “No, Don, that is not true.”
When Mr. Bryant was consulted, he said, “Three of these boys are always truthful but two will lie every time.”
Who took the apple?
Riddle AnswerThe Three Gods
Three Gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter.
Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one God. The Gods understand English, but will answer all questions in their own language, in which the words for yes and no are “da” and “ja”, in some order. You do not know which word means which.
- It could be that some God gets asked more than one question (and hence that some God is not asked any question at all).
- What the second question is, and to which God it is put, may depend on the answer to the first question. (And of course similarly for the third question.)
- Whether Random speaks truly or not should be thought of as depending on the flip of a coin hidden in his brain: if the coin comes down heads, he speaks truly; if tails, falsely.
- Random will answer “da” or “ja” when asked any yes-no question.
What would your three questions be?
Riddle Answer