# Average | Quantitative Aptitude

1. Average refers to the sum of numbers divided by n. Also called the mean average.

Average Formula = Sum of observations/ Number of observations

Some important properties of average are:

When the difference between all the items is same (and the number of terms is odd), then the average is equal to the middle term.

1. If x is added to all the items, then the average increases by x.
2. If x is subtracted from all the items, then the average decreases by x.
3. If every item is multiplied by x, then the average also gets multiplied by x.
4. If every item is divided by x, then the average also gets divided by x.

2. 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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