Answer:number of panels produced by Plant B = 4000
Explanations:
We are told that : 
• Plant ,A, produced ,8000, panels 
,
• Let ,b, be the number of ,panels produced by plant B 
,
• Therefore, total panels =, A+B= 8000+b 
The diagram below illustrates the conditions further 
From the diagram above, we can deduct that : 
1%A + 4% B = 2 % ( A+B) 

• This means that number of panels produced by Plant B = 4000