Shortcuts For Aptitude : (Topic - Average)

Important Things To Remember:

• Replacement case:

Weight of new person =  Weight of outgoing person  + No of person (inc in average)

Weight of new person = Weight of outgoing person  -  No of person (dec in average)

• Non replacement case:

Teacher age = Existing average + Total no of new persons (inc in average)

Teacher age = Existing average - Total no of new persons (dec in average)

• Diff of first & last no = Difference in Average * (Total no of sample-1)
• Correct average = Existing average ± (Diff in value/Total no of observation)
• If average of some numbers is “x” and a constant number is added to each term of the series, then new average is = x+a. Similarly calculate you can find new average when subtraction, multiplication and division to each term of the series is given.
• Average = Sum of observations / no of observations.