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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-9 section-2

Each section contains 100 MCQs on Average .
81
The mean high temperature of the first four days of a week is 25°C whereas the mean of the last four days is 25.5°C. If the mean of the whole week is 25.2°C, then the temperature of the 4th day is-
Discuss
Answer & Solution
Answer: Option C
Solution:
Average temperature of first four days = 25°C
Total temperature of first four days = 25° × 4 = 100°C
Average temperature last four days = 25.5°C
Total temperature of four days = 25.5° × 4 = 102°C
Total temperature of whole week = 25.2° × 7 = 176.4°C
∴ Temperature of the 4th day
= 100° + 102° - 176.4°
= 25.6°C
82
The average weight of A, B and C is 40 kgs. Weight of C is 24 kgs more than A’s weight and 3 kgs less than B’s weight. What will be the average weight of A, B, C and D, if D weights 15 kgs less than C?
Discuss
Answer & Solution
Answer: Option D
Solution:
Average weight of A, B and C = 40 kgs
Total weights of A , B and C = 40 × 3 = 120 kgs
Weight of C = (A + 24) and C = (B - 3)
∴ A + 24 = B - 3
⇒ B = A + 27
Now A + B + C = 120
⇒ A + A + 27 + A + 24 = 120
⇒ 3A + 51 = 120
⇒ A = $$\frac{69}{3}$$ = 23 kg
B = A + 27 = 23 + 27 = 50 kg
C = 120 - 23 - 50 = 47 kg
D = 47 - 15 = 32 kg
∴ Required average weight of A, B, C and D
= $$\frac{23 + 50 + 47 + 32}{4}$$
= $$\frac{152}{4}$$
= 38 kg
83
The average of 11 results is 60. If the average of first six results is 58 and that of last six is 63, find the 6th result-
Discuss
Answer & Solution
Answer: Option A
Solution:
The average of 11 results = 60
The total of 11 results = 60 × 11 = 660
Average of first six results = 58
Average of last six results = 63
Total of first six results = 58 × 6 = 348
Total of last six results = 63 × 6 = 378
∴ Sixth result = Total of first and last sixth results = Total of 11 results
= (348 + 378) - 660
= 726 - 660
= 66
84
The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is-
Discuss
Answer & Solution
Answer: Option B
Solution:
Let the ratio be K : 1
Then,
⇔ K × 16.4 + 1 × 15.4 = (K + 1) × 15.8
⇔ (16.4 - 15.8) K = (15.8 - 15.4)
⇔ K = $$\frac{0.4}{0.6}$$
⇔ K = $$\frac{2}{3}$$
∴ Required ratio
= $$\frac{2}{3}$$ : 1
= 2 : 3
85
The average score of a class of boys and girls in an examination is A. The ratio of boys and girls in the class is 3 : 1. If the average score of the boys is A + 1, the average score of the girls is-
Discuss
Answer & Solution
Answer: Option B
Solution:
Let the number of boys and girls in the class be 3x and x respectively.
Let the average score of the girls be y.
Then,
⇒ 3x (A + 1) + xy = (3x + x) A
⇒ 3 (A + 1) y = 4A
⇒ y = A - 3
86
Ten years ago, the ages of the members of a joint family of eight people added up to 231 years. Three years later, one member died at the age of 60 years and a child was born during the same year. After another three years, one more member died, again at 60, and a child was born during the same year. The current average of this eight-member joint family is nearest to-
Discuss
Answer & Solution
Answer: Option D
Solution:
Sum of the ages of 8 members, 10 years ago = 231 years
Sum of the ages of all members, 7 years ago
= (231 + 8 × 3 - 60) years
= 195 years
Sum of the ages of all members, 4 years ago
= (195 + 8 × 3 - 60) years
= 159 years
Sum of the present ages of all 8 members
= (159 + 8 × 4) years
= 191 years
∴ Current average age = $$\frac{191}{8}$$ years
= 23.8 years $$ \approx $$ 24 years
87
Four years ago, the average age of a family of four persons was 18 years. During this period, a baby was born. Today if the average age of the family is still 18 years, the age of the baby is
Discuss
Answer & Solution
Answer: Option B
Solution:
Sum of the ages of 4 members, 4 years ago
= (18 × 4) years
= 72 years
Sum of the ages of 4 members now
= (72 + 4 × 4) years
= 88 years
Sum of the ages of 5 members now
= (18 × 5) years
= 90 years
∴ Age of the baby
= (90 - 88) years
= 2 years
88
When the average age of a couple and their son was 42 years, the son married and got a child after one year. When the child was 5 years old, the average age of the family became 36 years. What was the age of daughter-in- law at the time of their marriage ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Sum of the ages of father, mother and son at the time of son's marriage
= (42 × 3) years
= 126 years
Sum of the present ages of father, mother and son
= (126 + 3 × 6)years
= 144 years
Sum of the present ages of father, mother, son and grandson
= (144 + 5) years
= 149 years
Sum of the present ages of father, mother, son, daughter-in-law and grandson
= (36 × 5) years
= 180 years
Daughter-in-law's present age
= (180 - 149) years
= 31 years
∴ Age of daughter-in-law at the time of marriage
= (31 - 6) years
= 25 years
89
The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is-
Discuss
Answer & Solution
Answer: Option B
Solution:
Sum of the present ages of husband, wife and child
= (27 × 3 + 3 × 3) years
= 90 years
Sum of the present ages of wife and child
= (20 × 2 + 5 × 2) years
= 50 years
∴ Husband's present age
= (90 - 50) years
= 40 years
90
Four years ago, the average age of A and B was 18 years. At present the average age of A, B, and C is 24 years. What would be the age of C after 8 years?
Discuss
Answer & Solution
Answer: Option D
Solution:
Sum of the present ages of A and B
= (18 × 2 + 4 × 2) years
= 44 years
Sum of the present ages of A, B and C
= (24 × 3) years
= 72 years
C's present age
= (72 - 44) years
= 28 years
∴ C's age after 8 years
= (28 + 8) years
= 36 years