Tuesday, 15 November 2016

Average - Quantative Aptitude

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Average (Quantitative Aptitude) for Bank PO, Clerk, SSC CHSL, CGL and other competitive exams Weighted Average and Average Speed

The average of a given set of number is a measure of the central tendency of the set. In other words, it is the mean value of a set of number or values. Therefore, average of a set of given n number is given by (x1+x2+x3+-----+xn)/n.

Average of some observation = sum of all observation/no of all observation.

Weighted Average

If average of n, quantities is x and that of n2 quantities is y, the average of total ( n1+n2) quantities is given by.
n1x
 + n2/n1 + n2

Average Speed

• Average speed = Total distance/Total time

The distance between two points A and B is d and speed is travelling from point A to B is x km/h and from point B to A is y km/h.

Then, Average speed = 2xy/x+y

Average of some important series of numbers
  • Average of odd numbers from 1 to n = (n+1)/2 , where n = last odd number.
  • The average of even number from 2 to n = (n + 2)/2,when n = last even number.
  • The average of square of natural numbers till. n = (n+1) (2n+1)/6.
  • The average of cubes of natural number till n = [ n ( n + 1 )2].
  • The average of first n consecutive odd number = n

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