This walks on graves at night yet in homes during the day,
Men are scared of it, women like it, children play with it,
It lives on dates and salt,
It is covered in hair,
Its name starts with ‘M’ and it is mentioned in the Quran.
Moths.
Most species of moths are nocturnal, yet they are attracted to light and can be found in homes. Men, in the most generic sense, can be scared of moths (see Mottephobia) as well as the damage they can cause as pests to bee hives, grain, flour, trees and agriculture. Women like moths because of the silk they produce. Children frequently chase and play with moths. Moths are attracted to salt and love to eat rotting fruit (such as dates). Some species of moths are densely covered with tiny hairs and of course it starts with the letter ‘m’. Lastly, moths are mentioned in the Quran (101:4 (Asad) [It will occur] on the Day when men will be like moths swarming in confusion)
A princess is as old as the prince will be when the princess is twice the age that the prince was when the princess’s age was half the sum of their present ages.
This one took a while to figure out and there are numerous valid ways of finding the answer.
Here is the solution I came up with
I created the following table from the riddle:
Current
Future
Past
Princess
x
2z
(x+y)/2
Prince
y
x
z
I then created three equations, since the difference in their age will always be the same.
d = the difference in ages
x – y = d
2z – x = d
x/2 + y/2 – z = d
I then created a matrix and solved it using row reduction.
x
y
z
1
-1
0
d
-1
0
2
d
.5
.5
-1
d
It reduced to:
x
y
z
1
0
0
4d
0
1
0
3d
0
0
1
5d/2
This means that you can pick any difference you want (an even one presumably because you want integer ages).
Princess age: 4d
Prince age: 3d
Ages that work
Princess
Prince
4
3
8
6
16
12
24
18
32
24
40
30
48
36
56
42
64
48
72
54
80
60
To see other solutions check out the comments from when I posted this on my blog.
The riddle refers to a variety of meanings of the word fine.
Feeling normal refers to when you feel fine.
Extremely thin refers to a fine thread.
A punishment refers to being charged a fee.
The one who wins refers to an athlete who is physically trained and hardened close to the limit of efficiency.
Free from impurity refers to measuring the fineness of precious metals.
A keen edge refers to a knife with a fine edge.
Refined refers to fine manners or elegance.
The most popular answer for this teaser is ‘today’. Of course this only works if you’re reading it on that particular date or if the date is not specified. Another option is to respond literally with ‘a date’. Lastly, certain dates could be squeezed into letters using Roman numerals if you abbreviate the year to 2 numerals. For example, January 20th, 2011 would be I XX XI.