Averages

Average is defined as the ratio of sum of the quantities to the number of quantities.

• If each number is increased or decreased by a certain quantity, then the average also increases or decreases by the same quantity.
• If each number is multiplied or divided by a certain quantity, then the average also gets multiplied or divided by the same quantity.

Tip: Suppose a man covers a certain distance at x kmph and an equal distance at y kmph, then the average speed during the whole journey is (2xy/x+y) kmph.
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