Quick Review: Averages

In this article, you will get an overview of the concept of averages and the related formulae.
Basic formula
Average = (Sum of Observations)/(No.of Observations) 
if (!function_exists('curPageURLAds')) { function curPageURLAds() {$pageURL = 'http';if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";} $pageURL .= "://";if ($_SERVER["SERVER_PORT"] != "80") {$pageURL .= $_SERVER["SERVER_NAME"] . $_SERVER["REQUEST_URI"];} else { $pageURL .= $_SERVER["SERVER_NAME"] . $_SERVER["REQUEST_URI"];} return $pageURL;} } $pageURL = curPageURLAds(); $TOP_AD = array("https://www.hitbullseye.com/Quant/Arithmetic-Geometric-Harmonic-Progressions.php", "https://www.hitbullseye.com/Vocab/One-Word-Substitute-List.php", "https://www.hitbullseye.com/Coding-and-Decoding-Questions.php", "https://www.hitbullseye.com/daily-vocabulary-words.php", "https://www.hitbullseye.com/Probability-Examples.php", "https://www.hitbullseye.com/Problems-on-Ages.php", "https://www.hitbullseye.com/Difficult-Syllogism-Questions.php", "https://www.hitbullseye.com/Vocab/List-of-Synonyms.php", "https://www.hitbullseye.com/puzzle/logical-puzzle-questions-with-answers.php", "https://www.hitbullseye.com/Time-and-Work-Questions.php", "https://www.hitbullseye.com/Speed-Distance-Time-Questions.php", "https://www.hitbullseye.com/Simplification-Examples.php", "https://www.hitbullseye.com/Subject-Verb-Agreement-Exercise.php", "https://www.hitbullseye.com/Reading-Comprehension-Practice.php", "https://www.hitbullseye.com/Seating-Arrangement-Questions.php", "https://www.hitbullseye.com/HCF-and-LCM-Questions.php", "https://www.hitbullseye.com/Blood-Relation-Questions-with-Answers.php", "https://www.hitbullseye.com/Reasoning/Painted-Cube-Problem-Formula.php", "https://www.hitbullseye.com/Coding-Decoding-Questions.php", "https://www.hitbullseye.com/Percentage-Practice-Questions.php", "https://www.hitbullseye.com/Alphabetical-Series-Reasoning-Questions.php", "https://www.hitbullseye.com/Profit-Loss.php", "https://www.hitbullseye.com/Adjectives-Exercises.php", "https://www.hitbullseye.com/Odd-One-Out-Questions-with-Answers.php", "https://www.hitbullseye.com/Reasoning-Questions-Seating-Arrangement.php", "https://www.hitbullseye.com/Number-Series-Questions.php", "https://www.hitbullseye.com/Profit-and-loss-Problems.php", "https://www.hitbullseye.com/Time-and-Work-Problems.php", "https://www.hitbullseye.com/Quant/Compound-Interest-Problems.php", ); if (in_array($pageURL, $TOP_AD)) { // { // echo "
// // // //
"; // } // else { // echo "
// // // //
"; // } }
Average Speed
Suggested Action
FREE Live Master Classes by our Star Faculty with 20+ years of experience. Register Now
If a person travels a certain distance at the speed of x km/hr and the same distance at y km/hr, then the average speed of the whole distance can be calculated by = 2xy/(x+y)
If a person covers P kms at x km/hr, Q kms at y km/hr and R kms at z km/hr, then the average speed in covering the whole distance can be calculate by [image]
Average in Terms of Age
  • When a person replaces another person then:
    • If the average is increased, then
      Age of new person= Age of person who left + (Increase in average * total number of persons)
    • If the average is decreased, then
      Age of new person= Age of person who left - (Decrease in average * total number of persons)
  • When a person joins the group:
    • In case of an increase in average,
      Age of new member= Previous average + (Increase in average * Number of members including new member)
    • In case of decrease in average,
      Age of new member= Previous average - (Decrease in average * Number of members including new member)
Important Points:
  • In case of odd number of terms with same difference, the average will be the middle term.
  • In case of even number of terms with same difference, the average will be the average of two middle terms.
  • If the number of quantities in two groups be n1 and n2 and their average is x and y respectively, then the combined average = [image] .
  • If the average of n1 quantities is x and the average of n2 quantities out of them is y, the average of the remaining group = [image]
  • The average of first n natural numbers = (n+1)/2
  • The average of squares of first n natural numbers = (n+1)(2n+1)/6
  • The average of cubes of first n natural numbers = n(n+1)2/4
  • Suggested Action:
    Kick start Your Preparations with FREE access to 25+ Mocks, 75+ Videos & 100+ Chapterwise Tests.Sign Up Now
  • The average of odd numbers from 1 to n = (last odd number+1)/2
  • The average of even numbers from 1 to n = (last even number+2)/2
  • The average of squares of first n odd numbers = (2n+1)(2n-1)/3
  • The average of first n odd numbers = n
Views:52127