12,000 panels are produced by Plant B.
Step-by-step explanation:
- Plant A produced 4000 panels.
- Plant B produced 'x' panels.
- Total panel produced by both A and B = (4000+x)
The percentage of defective panels,
6% of plant A + 2% of plant B = 3% of both A and B
6/100(4000) + 2/100(x) = 3/100(4000+x)
240 + 0.02x = 120 + 0.03x
240-120 = 0.03x-0.02x
120 = 0.01x
x = 120/0.01
x = 12,000
The plant B produced 12,000 panels.
