0.03*16000 + 0.1*b = 0.06*(16000+b) (counting defective panels) ====> 480 + 0.1b = 0.06*16000 + 0.06*b 480 + 0.1b = 960 + 0.06*b 0.1b - 0.06b = 960 - 480 0.04b = 480 ====> b == 12000. Answer. Plant B produces 12000 panels. Check. 0.03*16000 + 0.1*12000 = 1680; 0.06*(16000+12000) = 1680. ! Correct !