How to Compound Percentages | Best Math Review

When determining a percentage of a percentage of a whole, for example 15% of 20% of 1,500, there is a common mistake that people make. You do not want to add together 15% and 20% to get 35% and subtract that from 1,500. This will result in the incorrect answer; the 15% must come from the 20%, not the whole. The correct way to solve this problem is to first convert the percentage into a fraction (0.2 in this case). Then take the whole (1,500) and subtract the decimal multiplied by the whole: 1500 – 0.2*1,500 = 1,200. Repeat the process to find 15% of 1,200 (1,020).

Finding a Compound Percentage

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Last updated: 05/03/2018
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