View Full Version : Math Problem Been Bugging Me
antistuff
01-12-2006, 01:14 PM
I thought of this the other day and its been on my mind since.
Lets say you have a wheel that is divided into four sections. The sections are 1, 2, 3, and double. When you land on double you spin it again and now 1, 2 and 3 are worth double. You can keep doubling infinitly.
What is each spin of the wheel worth on average?
It looks like a calculus problem to me, but being the college dropout I am I have no idea how to solve this.
RocketManJames
01-12-2006, 01:56 PM
Here's my try.
1/4 * (1 + 2 + 3) + 1/4 * (1/4 * 2 * (1 + 2 + 3)) + 1/4 * (1/4 * (1/4 * 2^2 * (1 + 2 + 3))) + ...
I think it ends up looking like (1 + 2 + 3) * (1/4 + 1/8 + 1/16 + ...) = 6 * 1/2 = 3
Not 100% sure this is right, but this is what I came up with.
-RMJ
BruceZ
01-12-2006, 02:40 PM
[ QUOTE ]
Here's my try.
1/4 * (1 + 2 + 3) + 1/4 * (1/4 * 2 * (1 + 2 + 3)) + 1/4 * (1/4 * (1/4 * 2^2 * (1 + 2 + 3))) + ...
I think it ends up looking like (1 + 2 + 3) * (1/4 + 1/8 + 1/16 + ...) = 6 * 1/2 = 3
Not 100% sure this is right, but this is what I came up with.
-RMJ
[/ QUOTE ]
Right. Or more simply:
EV = (1/4)*1 + (1/4)*2 + (1/4)*3 + (1/4)*2*EV
(1/2)*EV = 3/2
EV = 3.
antistuff
01-12-2006, 04:39 PM
I guess I was along the right track. After thinking about it I figured that it is 1+2+3+what a double is worth / 4.
I'm still not sure I exactly understand it, but I'm closer now.
thanks.
BruceZ
01-12-2006, 04:41 PM
[ QUOTE ]
I guess I was along the right track. After thinking about it I figured that it is 1+2+3+what a double is worth / 4.
I'm still not sure I exactly understand it, but I'm closer now.
thanks.
[/ QUOTE ]
A double is worth twice what the whole game is worth, since when you get a double, the game starts over with everything being worth twice as much (2,4,6,double).
antistuff
01-12-2006, 05:04 PM
So its like infinitly recursive (reggresive?), how do you get a number for it?
BruceZ
01-12-2006, 05:35 PM
[ QUOTE ]
So its like infinitly recursive (reggresive?), how do you get a number for it?
[/ QUOTE ]
Right, it's a recursive equation for EV in the sense that EV appears on both sides of the equation. Just solve for EV like I did above.
notmyusername
01-12-2006, 08:39 PM
[ QUOTE ]
Right. Or more simply:
EV = (1/4)*1 + (1/4)*2 + (1/4)*3 + (1/4)*2*EV
(1/2)*EV = 3/2
EV = 3.
[/ QUOTE ]
Very elegant solution. Are you a mathematician?
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