A dealer sold two types of goods for 10,000 each. On one of them, he lost 20% and on the other he gained 20%. His gain or loss percent in the entire transaction was ?
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When two items are sold at the same price, and one has a P% profit and the other a P% loss, there is *always* a net loss. The loss percentage is simply $\left(\frac{P}{10}\right)^2\%$. Remember this shortcut for efficiency in competitive exams.