Quantitative Aptitude Topic of the day: Averages

Averages questions are quite easy to attempt if the concepts are clear.

Suppose there are N numbers, then their average is their sum divided by that is,

Average=(sum / N)

Weighted Average: The average between two sets of numbers is closer to the set with more numbers.
if 3 batsmen scored 25 runs and 2 batsmen scored 35 runs the average of the team won’t be 30. Rather it will be
= (25×3 + 35×2 )/5 = 29 . This is nearer to 25 since more batsmen scored 25 runs.

Attempt the following questions to check your level of preparedness for ratio proportion questions in competitive exams. You can answer the questions in comments section. Also make sure you checkout tomorrow’s Quantitative Lunch update for solutions to these questions along with the formulae used in VIDEO format by our Subject Expert.

Question 1 :The average weight of 11 players of Indian cricket team is increased by 1 kg, when one player of the team weighing 55 kg replaced by a new player. The weight of the new player is:

A) 55 kg
B) 64 kg
C) 66 kg

Question 2: The average age of 30 students of a class is 30 years. When the average age of class teacher is also included, the average age of the whole class increases by 1 year. This age of the class teachers is:

A)31 years
B) 60 years
C) 61 years
D) 65 years

Question 3: The average of first 100 natural number is :

A) 100
B) 50
C) 50.5
D) 55

Question 4: The average of first 50 odd natural numbers is

A) 50
B) 55
C) 51
D) 101

Question 5: The average of first 99 even numbers is :

B) 100
C) 9801
D) 9009

Share these questions with everyone you know and check their answers. Also let us know your comments on video solutions.



  1. Wow Raj all your answers are correct except for the second question. The second answer isnt correct. I believe it should be 61. i.e. option b

    This age of the class teachers=31 x 31 – 30 x 30 = 61 years

  2. 5. The average of first 99 even numbers = (2+4+ 6+…..+198)/99 = 100

    Use an AP sum to solve the problem = (n/2)(a + l) = 99/2 (2+198) = 9900 => 9900/99 = 100.

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