Two factory plants are making TV panels. Yesterday, Plant A produced 6000 panels. Four percent of the panels from Plant A and 1% of the panels from Plant B were defective. How many panels did Plant B produce, if the overall percentage of defective panels from the two plants was 2% ?

Question

jack1 · Answer

Always move from the known to the unknown @cpcano :

Plant A produced 6000 panels. 
--> A = 6000

Four percent of the panels from Plant A and 1% of the panels from Plant B were defective.
--> A x 0.04          and     B x 0.01     were defective
--> 6000 x 0.04     and     B x 0.01     were defective
-->  240   +   0.01B         panels were defective

Overall percentage of defective panels from the two plants was 2%
--> 240   +   0.01B      =   (A + B) x 0.02
--> 240   +   0.01B      =   0.02A  +  0.02B  
--> 240   +   0.01B      =   0.02 x 6000    + 0.02B
--> 240   +   0.01B      =   120    + 0.02B
--> 240   -   120          =    0.02B   -  0.01B
-->  120                       =    0.01B

therefore B = ???
How many panels did Plant B produce? @cpcano