Average - Quantitative Aptitude Questions and Answers
This section focuses on "Average" in Quantitative Aptitude. These Multiple Choice Questions (mcq) should be practiced to improve the Quantitative Aptitude skills required for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams and other competitive examinations.
1. Find the average of even numbers above 1000 & upto 1 lakh?
Explanation: No of even numbers upto 1lkah = 50000
No of even numbers upto 1000 = 500
No of even numbers above 1000 & upto 1 lakh= 49500
sum of first N even numbers = N*N
sum of even numbers above 1000 & upto 1 lakh = 50000*50000 - 500*500 = 2499750000
average of even numbers above 1000& upto 1 lakh = 2499750000/ 49500 = 50500
2. The average age of 11 daughters of a family is 12yrs. Average age of the daughters together with their
parents is 27yrs. If mother is 14yrs younger than father. Then find the father's age.
Explanation: Total age of 11 daughters of a family = 11*12 = 132
father age = 14 +mother age
total age of the family
(11 daughters + father + mother) is,
132+mother +14+ mother = 27 * 13
mother = 102.5
father age = 14+102.5 =116.5years
3. Rohit married 21 years ago at the age of 90 years. His wife's present age 99years. If 24 years later the
average age of rohit, his wife and their son was 90 years, then what is son's present age?
Explanation: Rohit present age = 111years
total age of family after 24 yrs = 90*3= 270
present age of rohit & his wife = 111+99 = 210yrs
present age of rohit, his wife & his son= 270- 24*3 =198
present age of son= 210-198=12yrs
4. The average height of a batch is 344 cm. 16more students with an average height of 320 cm joined the
batch therefore decreasing the average height of the batch by 12 cm. Find the total strength of the batch?
Explanation: let the initial strength of the batch be X
total height of the batch initially = 344X
total height of 16 new students = 320 * 16 = 5120 cm
Then, the average height of X+ 16students = 332
332 = [5120 + 344 X]/ [X + 16]
X= 16 students
5. When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by
400 g. What is the average weight of the remaining 119 students?
Explanation: Let the average weight of the 119 students be X.
Therefore, the total weight of the 119 of them will be 119X.
The questions states that when the weight of this student who left is added, the total weight of the class
When this student is also included, the average weight decreases by 0.4 kgs.
6. In an competitive examination, the average was found to be 72 marks. After detecting the errors the
marks of 94 candidates had to be charged from 90 to 66 each, and the average is reduced to 64 marks. Find
the total number of candidates who took the exam?
Explanation: let the number of candidates be A
total marks of candidates = 72A
after detecting error the change of marks for one candidate = 90 - 66 = 24 marks
change of marks for 94 candidates = 94*24 =2256
after detecting error of N candidates = 64A
then, 72A- 2256= 64A ,
7. A batsman average for 20 innings is 25 runs. His highest score exceeds his lowest score by 64 runs. If
these 2 innings are excluded, the average of the remaining 18 innings is 24 runs. The highest score of the
Explanation: Let the highest score be x
Then lowest score = x-64
Then (25 *20)- 18 * 24 = 432
8. The batting average of runs of a cricket player of 30 innings was 96. How many runs must he make in his
next innings so as to increase his average of runs by 12?
Explanation: Given that the total average runs of a cricket player (30 innings) = 96
After 31 innings = 108
Required number of runs = (108 * 31 – (96 *30)
=3348 – 2880
9. An Aided school has only three classes which contain 70, 36 and 40students respectively. The pass
percentage of these classes are30,25 and 20 respectively. The pass percentage of the aided school is
Explanation: Total number of students passed in class1 = 30/100 *70 = 21
Total number of students passed in class 2= 25/100 *36 = 9
Total number of students passed in class 3= 20/100 *40 = 8
Total number of students passed in the school = 38
Thus, pass percentage of the school = 38 /146*100 = 26 %
10. The average weight of M,N and O is 168 kg. If P joins the group, the average weight of the group
becomes 160 kg. If another man Q who weighs 6kg more than P replaces M, then the average of N,O,P and
Qbecomes158 kg. What is the weight of M?
Explanation: M+N+O =168 * 3 =504
P=136 kg and Q =142 kg
N+O+P+Q =158*4 =632
N+O+P =632-142 =490 ---->(2)
from 1 & 2,
11. At the average age of siva and sasi is equal to the average age of somu and ramu. if the ratio of age of
siva and sasi 1:3 and somu age is equal to the three by two of siva age. What is the present age of somu if
ramu age is 25years?
siva+sasi/2=somu + ramu/2
Siva’s age is 10 then somu's age = 3/2×10=15 years
12. The mean of 8 article was found to be 15. On rechecking, it was found that two article were wrongly taken
as 11 and 9 instead of 16 and 14 respectively. Find the correct mean.
Explanation: Calculated mean of 8 articles = 15
Incorrect sum of these 8 articles = (15*8) = 120.
Correct sum of these 8 articles
= (incorrect sum) - (sum of incorrect articles) + (sum of actual articles)
= [120 - (20) + (30)]
Therefore, correct mean = 130/8 = 16.25
Hence, the correct mean is 16.25
13. The average marks obtained by a student in Tamil, english, maths, science, and social together is 65%
above the average mark obtained in maths and science together. How many more marks exceeded by the
average of maths and science together than the sum of the tamil and english together?
Explanation: According to the question There is no other information about the marks in any one of the subject. The data gives is insufficient to answer the question.
14. Gowshik is going to market from his home by bike at a speed of 20kmph. While he comes back to his
home with a speed of X kmph, what should be the value of x so that his average speed is 24kmph ?
Explanation: Let speed be X
Average speed =2xy/(x+y)
15. The Cricketer average score in 40 over is 21, if the man scores 23runs in 8over, 26 runs in 10 over and
18runs in 14 over. What is the average score in remaining over?
Explanation: According to the question
16. The average marks of a class of 90 students is 126. Out Of them, 4 scores zero, first 60 students scored
an average of 116, next 24 scored an average of 118. What is the mark obtained by the remaining student in
Explanation: According to the question,
17. The average weight of a group of 22students is 34kg. When the weight of the staff is also included, the
average weight increases by 2kg. What is the weight of the staff?
Explanation: The average weight of a group of 22students = 34 kgs.
Therefore, the total weight of the group = 22*34 = 748 kg
When the weight of the staff is included, there are 23 individuals.
The average weight increases by 2kg. That is the new average weight = 36 kgs.
Therefore, the total weight of the 22 students plus the staff = 23* 36= 828
18. When the average age of a father, mother and their son was 90 years, the son got married and a child
was born just 6 year after the marriage when child turned 14 years the average age of the family is 80yrs.
Find the age of daughter - in - law at present?
Explanation: Total age of father, mother and son at the time of son's marriage = 90*3 =270
present age of family father, mother, son, daughter-in-law, child = (father, mother, son age at the time of
marriage) + daughter-in-law present age + child present age
= (270+60)+ daughter-in-law present age + 14 = 80*5 =400
daughter-in-law present age= 400-344 = 56yrs
19. The average of the 3 digit number, which remain the same when the digits interchange their positions is.
Explanation: Average = (111+222+333+444+555+666+777+888+999)/9
=4440 + 555/9
20. The average age of the men in a team is 76 years and that of the women is 75 years. The average age for the whole team is
Explanation: Clearly to find the average, we ought to number of men, women or total persons in the class, neither of which has been given. So the data provided is inadequate