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One-fifth of the light switches produced by a cer tain [#permalink]
15 Oct 2005, 22:17
19. One-fifth of the light switches produced by a cerÂ¬tain factory are defective. Four-fifths of the defective switches are rejected and of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective?