Riddle: I like indigo but not blue, I like onions but not turnips, I like forms but not shapes. According to the same rule, do I like tomatoes or avocados?

Answer: Avocadoes - I like all things that start with a preposition.

Riddle: It's always 1 to 6, it's always 15 to 20, it's always 5, but it's never 21, unless it's flying.
What is it?

Answer: The answer is: a dice. An explanation: "It's always 1 to 6": the numbers on the faces of the dice, "it's always 15 to 20": the sum of the exposed faces when the dice comes to rest after being thrown, "it's always 5": the number of exposed faces when the dice is at rest, "but it's never 21": the sum of the exposed faces is never 21 when the dice is at rest, "unless it's flying": the sum of all exposed faces when the dice is flying is 21 (1 + 2 + 3 + 4 + 5 + 6).

Riddle: A boy leaves home in the morning to go to school. At the moment he leaves the house he looks at the clock in the mirror. The clock has no number indication and for this reason, the boy makes a mistake in interpreting the time (mirror-image). Just assuming the clock must be out of order, the boy cycles to school, where he arrives after twenty minutes. At that moment the clock at school shows a time that is two and a half hours later than the time that the boy saw on the clock at home. What time is it?

Answer: The difference between the real time and the time of the mirror image is two hours and ten minutes (two and a half hours, minus the twenty minutes of cycling). Therefore, the original time on the clock at home that morning could only have been five minutes past seven: The difference between these clocks is exactly 2 hours and ten minutes (note that also five minutes past one can be mirrored in a similar way, but this is not in the morning!). Conclusion: The boy reaches school at five minutes past seven plus twenty minutes of cycling, which is twenty-five minutes past seven!...

Riddle: A woman is walking down a street night at a constant pace. As she passes the street light, she notices that her shadow becomes longer. Does the top of her shadow move faster, slower or the same when the shadow is longer as when it is shorter?

Answer: This point maintains a constant speed, independent of the lenght of the shadow.

Riddle: There are three guards and three prisoners who need to cross a river. Their boat only holds two people at a time, and the number of prisoners must NEVER be allowed to outnumber the number of guards on either side of the river; otherwise, the prisoners will overpower the guards and, well, the story will come to an abrupt end. List each of the trips that need to be made and who is in the boat, and who is on each of the riverbanks during each trip. How many trips it will take to safely transport all of the guards and prisoners across the river?

Answer The riddle "GUARDS AND PRISONERS" is unanswered.
ANSWER

Riddle: Ben walked into a hardware store and asked the price of some items. The salesman said: One costs $1, Eight costs $1, Seventeen cost $2, One hundred four costs $3 and One thousand seventy two costs $4. What was Ben buying?

Answer: Ben was buying home address numbers and they cost $1 per digit.

Riddle: How can this be true? Have a look at the picture. All the lines are straight, the shapes that make up the top picture are the same as the ones in the bottom picture so where does the gap come from?

Answer: The green triangle has dimensions 2 x 5 and gradient 2 / 5 = 0.4 The red triangle has dimensions 3 x 8 and gradient 3 / 8 = 0.375 Hence the gradient of the green triangle is greater than that of the red triangle.

Riddle: A man enters an expensive restaurant and orders a meal. When the waiter brings him his meal the man takes out a slip of paper and writes down 102004180, then leaves. The cashier hands the slip of paper to the cashier who understood it immediately.
What did the slip of paper say?

Answer: I =1, 0=Ought, 2=To, 0=Owe, 0=Nothing, 4=For, 1=I, 8=Ate, 0=Nothing. I Ought To Owe Nothing For I Ate Nothing. 102004180