Karina is deciding whether to use Brand A or Brand B motor oil in her car. Brand A costs 50% more per liter than Brand B. But, according to the recommendations for frequency of oil changes, if she uses Brand A, she will be able to drive 2.5 times as many kilometers before she changes her oil as she will if she uses Brand B. The cost per kilometer driven is what percent less when using Brand A than when using Brand B ?
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