plants and defective panels

Question

Two factory plants are making TV panels. Yesterday, Plant A produced 4 times as many panels as Plant B. Four percent of the panels from Plant A and 2 percent of the panels from Plant B were defective. How many panels did Plant B produce, if the two plants together produced 1800 defective panels?

Answer 1

A = 4B

0.04A + 0.02B = 1800

So, 0.04(4B) + 0.02B = 1800

0.18B = 1800

Solve for B.