Brain Teasers

[BringBackFergy]

A guy buys a cow for $60, then sells it for $70. 
 

He buys it back again for $80, then sells it again for $90. 
 

How much money did he make?

[Augie]

 

I don’t suppose “he made hamburgers” is an option? 

[BringBackFergy]

50 minutes ago, Augie said:

 

I don’t suppose “he made hamburgers” is an option? 

What’s his “income” or “profit”?

 

[Mike in Horseheads]

$10

[Special K]

Twenty bucks.