<p>Man has blue and red marbles. If he has more red marbles then blue one he wants to exchange one red for two blue($1R:2B$). If otherwise (more blue then red)he wants to exchange one blue for two red($1B:2R$). Are preferences of this man convex preferences?</p>

<p>My guess is that they are convex because linear combination of random bundles is worse than any chosen. Am i right?</p>

CC BY-SA 3.0
2015-11-04T13:33:01.523Z
We usually answer such questions by turning them into symbols and work the resulting expressions. Otherwise, a mistaken answer is the most frequent one.
Alecos Papadopoulos
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2015-11-04T13:35:15.170Z
I do not know how to write this specific "exchange" rate in symbols. I have changed something in the question is this what you meant?
mkropkowski
CC BY-SA 3.0
2015-11-04T18:17:50.663Z
@mkropkowski I believe what Alecos Papadopoulos meant was that you are supposed to give the equation of an indifference curve for this preference and apply the formal definition of convexity to points thereof.
Giskard
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2015-11-04T18:45:14.467Z
The point is that i do not have the equation of indifference curve, i have to figure out the shape using the informations provided.
mkropkowski
CC BY-SA 3.0
2015-11-04T18:54:40.847Z
Furthermore if i have chose to waste my time to post that on this page this means that i do not know how to do that thus i need a bit more sophisticated answer.
mkropkowski
CC BY-SA 3.0
2015-11-05T12:00:12.460Z
For the record: no one is obligated to answer your unspecific question. If you feel that opening a question here is a waste of time, why do you even bother to open a thread in the first place? And yes, you're right that preferences are not convex. Draw a $(R,B)$ plane with a 45° $R=B$ line through $(0,0)$. For $R<B$ the slope of the indifference curve is given by $\Delta B = -0.5 \Delta R$ and for $R>B$ by  $\Delta B = -2 \Delta R$. Now start from an arbitrary point on $R=B$ and draw the indifference curve according to the slopes. You'll realize that $R=B$ gives highest utility.
clueless
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2015-11-05T16:47:52.610Z
Thank you, appreciate your answer, but remember the point is that i have no other informations to specify the question all i knew was posted here thus i have no possibility to make this question more specific.
mkropkowski
<microeconomics><preferences>
Convex consumer preferences
mkropkowski
# Convex consumer preferences

(Asked by: username_0 on 2015-11-04)

Man has blue and red marbles. If he has more red marbles then blue one he wants to exchange one red for two blue($1R:2B$). If otherwise (more blue then red)he wants to exchange one blue for two red($1B:2R$). Are preferences of this man convex preferences?

My guess is that they are convex because linear combination of random bundles is worse than any chosen. Am i right?

**Tags:** microeconomics, preferences

> **Comments:**
> **username_1**: We usually answer such questions by turning them into symbols and work the resulting expressions. Otherwise, a mistaken answer is the most frequent one.  
> **username_0**: I do not know how to write this specific "exchange" rate in symbols. I have changed something in the question is this what you meant?  
> **username_2**: @username_0 I believe what username_1 meant was that you are supposed to give the equation of an indifference curve for this preference and apply the formal definition of convexity to points thereof.  
> **username_0**: The point is that i do not have the equation of indifference curve, i have to figure out the shape using the informations provided.  
> **username_0**: Furthermore if i have chose to waste my time to post that on this page this means that i do not know how to do that thus i need a bit more sophisticated answer.  
> **username_3**: For the record: no one is obligated to answer your unspecific question. If you feel that opening a question here is a waste of time, why do you even bother to open a thread in the first place? And yes, you're right that preferences are not convex. Draw a $(R,B)$ plane with a 45° $R=B$ line through $(0,0)$. For $R<B$ the slope of the indifference curve is given by $\Delta B = -0.5 \Delta R$ and for $R>B$ by  $\Delta B = -2 \Delta R$. Now start from an arbitrary point on $R=B$ and draw the indifference curve according to the slopes. You'll realize that $R=B$ gives highest utility.  
> **username_0**: Thank you, appreciate your answer, but remember the point is that i have no other informations to specify the question all i knew was posted here thus i have no possibility to make this question more specific.  

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