Answer:
Cash A/c Dr. 400 
 $12 = $4,800
 To Treasury Stock A/c 400 
 $10 = $4,000
 To Additional Paid In Capital 400 
 $2 = $800
(Sale of treasury stock, on premium of $2)
Step-by-step explanation:
When originally the treasury stock was purchased then the entry would be:
Treasury Stock A/c Dr. 1,000 
 $10
 Cash A/c $10,000
Recording purchase of treasury stock.
Now when the stock is sold for $12 each, then the amount of $2 = $12 - $10 = Additional Paid in Capital.
Therefore entry will be:
Cash A/c Dr. 400 
 $12 = $4,800
 To Treasury Stock A/c 400 
 $10 = $4,000
 To Additional Paid In Capital 400 
 $2 = $800
Sale of treasury stock, on premium of $2