Answer: hello your question is incomplete attached below is the missing information
Answer : 
$900
$600
<u>Given the new price of $4 by Government </u>
quantity demanded = 400 units 
quantity supplied = 150 units 
quantity bought and sold = 150 units
Explanation:
Consumer surplus  ( area below demand curve and above $300  
= Area of triangle = 0.5 * base * height 
= 0.5 * 300 ( 12 - 6 )  = $900
producer surplus ( area above supply curve and below $300 
=  Area of the triangle = 0.5 * 300 ( 6-2 ) = $600
<u>Given the new price of $4 by Government </u>
quantity demanded = 400 units 
quantity supplied = 150 units 
quantity bought and sold = 150 units
Consumer surplus ( area of triangle + area of rectangle )
 = 0.5 * 150 * ( 12-9 )+ L*B
= 0.5 * 150 * ( 3 ) + 150 * ( 9 - 4 )  = $975
producer surplus ( Area of triangle )
= 0.5 * 150 * (4-2) = $150
deadweight loss ( area of triangle ) 
= 0.5 * ( 300 - 150 ) ( 9-4 )
= $375