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Average - Aptitude MCQ Questions and Solutions with Explanations

Average MCQ Questions and answers with easy and logical explanations.Arithmetic Ability provides you all type of quantitative and competitive aptitude mcq questions on Average with easy and logical explanations. Average MCQ is important for exams like Banking exams,IBPS,SCC,CAT,XAT,MAT etc. Page-1 section-2

Each section contains 100 MCQs on Average .
1
The average age of seven boys sitting in a row facing North is 26 years. If the average age of the first three boys is 19 years and the average age of the last three boys is 32 years, what is the age of the boy who is sitting in the middle of the row?
Discuss
Answer & Solution
Answer: Option C
Solution:
Age of the boy sitting in the middle
= [26 × 7 - (19 × 3 + 32 × 3)]
= (180 + 153) years
= 29 years
2
The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is:
Discuss
Answer & Solution
Answer: Option D
Solution:
Let A, B, C represent their respective weights.
Then, we have :
A + B + C = (45 × 3) = 135.....(i)
A + B = (40 × 2) = 80.....(ii)
B + C = (43 × 2) = 86.....(iii)
Adding (ii) and (iii), we get:
A + 2B + C = 166.....(iv)
Subtracting (i) from (iv), we get: B = 31
∴ B's weight = 31 kg
3
The average weight of 45 students in a class is 52 kg. Five of them whose average weight is 48 kg leave the class and other 5 students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class?
Discuss
Answer & Solution
Answer: Option C
Solution:
Sum of the weights of the students after replacement
= [(52 × 45) - (48 × 5) + (54 × 5)] kg
= 2370 kg
∴ New average
= $$\left( {\frac{{2370}}{{45}}} \right)$$ kg
= $$52\frac{2}{3}$$ kg
4
The captain of a cricket team of 11 members is 26 years old and the wicket keeper is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average of the whole team. What is the average age of the team?
Discuss
Answer & Solution
Answer: Option A
Solution:
Let the average age of the whole team be x years.
∴ 11x - (26 + 29) = 9 (x - 1)
⇒ 11x - 9x = 46
⇒ 2x = 46
⇒ x = 23
So, the average age of the team is 23 years.
5
A motorist travels to a place 150 km away at an average speed of 50 km/hr and returns at 30 km/ hr. His average speed for the whole journey in km/hr is-
Discuss
Answer & Solution
Answer: Option C
Solution:
Average speed
$$\eqalign{ & = \left( {\frac{{2xy}}{{x + y}}} \right){\text{ km/hr}} \cr & = \left( {\frac{{2 \times 50 \times 30}}{{50 + 30}}} \right){\text{ km/hr}} \cr & = 37.5{\text{ km/hr}} \cr} $$
6
The average age of a husband and wife at the time of their marriage was 25 years. A son was born to them two years after their marriage. The present average age of all three of them is 24 years. How many years is it since the couple got married?
Discuss
Answer & Solution
Answer: Option C
Solution:
Sum of the ages of husband and wife at the time of their marriage
= (25 × 2) yrs
= 50 yrs
Sum of the ages of husband and wife when their son was born
= (50 + 2 × 2) yrs
= 54 yrs
Sum of the ages of husband, wife and son at present
= (24 × 3) yrs
= 72 yrs
∴ Age of son = $$\frac{{\left( {72 - 54} \right)}}{3}$$   = $$\frac{{18}}{3}$$   = 6 years
Hence, the couple got married (6 + 2) = 8 years ago
7
The average age of a group of persons going for picnic is 16 years. Twenty new persons with an average age of 15 years join the group on the spot due to which their average age become 15.5 years. The number of persons initially going for picnic is -
Discuss
Answer & Solution
Answer: Option C
Solution:
Let the initial number of persons be x.
Then,
⇒ 16x + 20 × 15 = 15.5 (x + 20)
⇒ 0.5x = 10
⇒ x = 20
8
A certain factory employed 600 men and 400 women and the average wage was Rs. 25.50 per day. If women got Rs. 5 less than a man, then what are their daily wages?
Discuss
Answer & Solution
Answer: Option B
Solution:
Let the daily wage of a man be Rs. x
Then, daily wage of a woman = Rs. (x - 5)
Now,
⇒ 600x + 400(x - 5) = 25.50 × (600 + 400)
⇒ 1000x = 27500
⇒ x = 27.50
∴ Man's daily wages = Rs. 27.50
Woman's daily wages = (x - 5) = Rs. 22.50
9
A coaching institute has students in 3 batches – X, Y and Z. In a certain examination, the average marks obtained by these batches are 72, 60 and 50 respectively. The average marks of batches X and Y taken together is 69. If the ratio of the number of students in batches Y and Z is 6 : 7. What is the average score of all the three batches put together?
Discuss
Answer & Solution
Answer: Option D
Solution:
Let the number of students in batches Y and Z be 6x and 7x respectively, and the number of students in batch X be y.
Then,
$$\eqalign{ & \Rightarrow 72y + 60 \times 6x = 69\left( {6x + y} \right) \cr & \Rightarrow 72y + 360x = 414x + 69y \cr & \Rightarrow 3y = 54x \cr & \Rightarrow y = 18x \cr} $$
∴ Required average

$$\eqalign{ & = \frac{{72 \times 18x + 60 \times 6x + 50 \times 7x}}{{18x + 6x + 7x}} \cr & = \frac{{1296 + 360 + 350}}{{31}} \cr & = \frac{{2006}}{{31}} \cr & = 64.7 \cr} $$
10
In an engineering college the average salary of all engineering graduates from Mechanical trade is Rs. 2.45 lacs per annum and that of the engineering graduates from Electronics trade is Rs. 3.56 lacs per annum. The average salary of all Mechanical and Electronics graduates is Rs. 3.12 lacs per annum. Find the least number of Electronics graduates passing out from this institute.-
Discuss
Answer & Solution
Answer: Option C
Solution:
Let the number of Mechanical Engineering graduates be M and the number of Electronics Engineering graduates be E.
Then,
  $$ \Rightarrow 2.45M + 3.56E = $$    $$3.12\left( {M + E} \right)$$
  $$ \Rightarrow 2.45M + 3.56E = $$    $$3.12M + 3.12E$$
$$\eqalign{ & \Rightarrow 0.44E = 0.67M \cr & \Rightarrow \frac{M}{E} = \frac{{0.44}}{{0.67}} = \frac{{44}}{{67}} \cr} $$
Since the ratio 44 : 67 is in its simplest form,
So least number of Electronics graduates = 67