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.
I’m built from anything you don’t like,
You’re using me right now in fact,
I am one but represent many,
When attacked I’m easily cracked,
I’m created in seconds but live forever
And though you may not understand,
I’ll help you do well but be careful my friend,
Hurt me and you won’t withstand.
Kids are often told, when dealing with unpleasant things, that it builds character. You’re reading the characters this riddle is written with. In computer science a char is often represented by one byte and can store any character you want.
When politicians have their character besmirched it can swiftly change the voting public’s mind about them. Characters in novels are created with a few lines but live on in our memories. And if your character or reputation is damaged, you may find it hard to deal with the aftermath.
And here’s a great quote from Warren Buffet on your character.
“It takes 20 years to build a reputation and five minutes to ruin it. If you think about that, you’ll do things differently.” — Warren Buffet
I drift forever with the current
down these long canals they’ve made
Tame, yet wild, I run elusive
Multitasking to your aid.
Before I came, the world was darker
Colder, sometimes, rougher, true
But though I might make living easy,
I’m good at killing people too.