AVERAGES, ALLIGATIONS AND MIXTURES LESSON -1 Overview

AVERAGES Sum of all items in the group Number of items in the groujp Ex: Suppose there are 30 students in class: Avg height = sum of heights of all students Number of students in class

Average is also called mean value If the value of each item is increased by a same value 'x' then the avg of the group of items also increases by x'. If a value of each item is multiplied by the same value 'x' then the avg of a group of items also gets multiplied by 'x'.

WEIGHTED AVERAGE : it's the average of two different groups. Ex: avg height of class 'a' of strength 30 -150 avg height of class 'b' of strength 20 -100 Weighted avg = 30x150 + 20x100 = 130 3020

MIXTURES Weighted avg can be calculated for any mixture. Suppose: q1- quantity of an item of quality p1 q2 quantity of another item of quality p2 Weighted avg, p - p1q1 + p2q2 q1+q2

ALLIGATIONS Rule of alligation: q2 p-p1 quantity of cheaper quantity of dearer rate of dearer-average rate average rate-rate of cheaper

Dearer price Cheaper price AVERAGE PRICE Avg price-Chper priceDearer price-avg price

Suppose a container contains 'x' units of liquid from which 'y' units are taken out and replaced by water. Then after 'n' operations: Quantity of pure liquid = (x-y)n = k(say)

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Varsha Pujari

I talk a lot, I like reading novels, playing tennis,watching TV, learning & trying out new things in life & love being around my dogs

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Deepak sharma

a year ago

Helpful, please make more such lessons

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