Average MCQs for Competitive Examination
Solve the following problems.
Q. 81
A company produces an average of 4000 items per month for the first 3 months. How much items, it must produce on an average per month over the next 9 months to average 4375 items per month over the whole year?
(A) 4500
(B) 4600
(C) 4680
(D) 4710
Answer: (A) 4500
Explanation: N/A
Q. 82
Average age of 6 sons of a family is 8 years. Average age of sons together with their parents is 22 years. If the father is older than the mother by 8 years, the age of mother is
(A) 44
(B) 52
(C) 60
(D) 68
Answer: (C) 60
Explanation: N/A
Q. 83
The average monthly income of certain agricultural workers is S and that of other workers is T. The number of agricultural workers is 11 times that of other workers. Then, the average monthly income of all the workers is
(A) (S + 11T)/12
(B) (S + T)/12
(C) (11S + T)/12
(D) (1/11S) + T
Answer: (C) (11S + T)/12
Explanation: N/A
Q. 84
The average of the squares of first ten natural numbers is
(A) 35.5
(B) 36
(C) 37.5
(D) 38.5
Answer: (D) 38.5
Explanation: N/A
Q. 85
The average of odd numbers up to 100 is
(A) 50.5
(B) 50
(C) 49.5
(D) 49
Answer: (B) 50
Explanation: N/A
Q. 86
If the average of x and 1/x (x ≠ 0) is M, then the average of x² and (1/x)² is
(A) 1 – M²
(B) 1 – 2M
(C) 2M² – 1
(D) 2M² + 1
Answer: (C) 2M² – 1
Explanation: N/A
Q. 87
The average mathematics marks of two sections A and B of class IX in the annual examination is 74. The average marks of Section A is 77.5 and that of Section B is 70. The ratio of the number of students of Section A and B is
(A) 7 : 8
(B) 7 : 5
(C) 8 : 7
(D) 8 : 5
Answer: (C) 8 : 7
Explanation: N/A
Q. 88
There are in all, 10 balls; some of them are red and the others white. The average cost of all balls is Rs 28. If the average cost of red balls is Rs 25 and that of white balls is Rs 30. The number of white balls is
(A) 3
(B) 5
(C) 6
(D) 7
Answer: (C) 6
Explanation: N/A
Q. 89
The average of x number is y² and the average of y numbers is x². So the average of all the numbers taken together is
(A) (x³ + y³)/(x + y)
(B) xy
(C) (x² + y²)/(x + y)
(D) xy² + yx²
Answer: (B) xy
Explanation: N/A
Q. 90
The average of 5 consecutive integers starting with m is n. What is the average of 6 consecutive integers starting with (m + 2)?
(A) (2n + 5)/2
(B) (n + 2)
(C) (n + 3)
(D) (2n + 9)/2
Answer: (A) (2n + 5)/2
Explanation: N/A
Q. 91
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 (in kg) of B is
(A) 17
(B) 31
(C) 26
(D) 20
Answer: (B) 31
Explanation: N/A
Q. 92
The average of the first three numbers is double the fourth number. If the average of all four numbers is 12, find the fourth number
(A) 16
(B) 20
(C) 48/7
(D) 18/7
Answer: (C) 48/7
Explanation: N/A
Q. 93
The average marks of 28 students in Mathematics was 50; 8 students left the school, then this average increased by 5. What is the average of marks obtained by the students who left the school?
(A) 50.4
(B) 37.5
(C) 42.5
(D) 45
Answer: (B) 37.5
Explanation: N/A
Q. 94
The average age of P, Q and R is 5 years more than R’s age. If the total ages of P and Q together is 39 years, then R’s age is
(A) 14 years
(B) 16 years
(C) 24 years
(D) 12 years
Answer: (D) 12 years
Explanation: N/A
Q. 95
The average age of A and B is 20 years. If A is to be replaced by C, the average would be 19 years. The average age of C and A is 21 years. The ages of A, B and C in order (in years) are
(A) 18, 22, 20
(B) 18, 20, 22
(C) 22,18, 20
(D) 22, 20, 18
Answer: (C) 22, 18, 20
Explanation: N/A
Q. 96
A man’s pension on retirement from service is equal to half the average salary during the last 3 years of his service. His salary from 1 January 1983 is Rs 380 per month with an increment of Rs 40 due on 1 October 1983, 1 October 1984 and 1 October 1985. If he retires on 1 January 1986, what pension does he draw per month?
(A) Rs 215
(B) Rs 205
(C) Rs 225
(D) Rs 230
Answer: (A) Rs 215
Explanation: Avg = (380 * 9 + 420 * 12 + 460 * 12 + 500 * 3)/(9 + 12 + 12 + 3) = 430
Pension per month = 430/2 = 215
Q. 97
The average salary of all staff of a school is Rs 10,000. The average salary of 20 teaching staff is Rs 12,000 and that of non-teaching staff is Rs 5000. The number of non-teaching staff will be
(A) 7
(B) 8
(C) 10
(D) 12
Answer: (B) 8
Explanation: N/A
Q. 98
In the afternoon, a student read 100 pages at the rate of 60 pages per hour. In the evening, when she was tired, she read 100 more pages at the rate of 40 pages per hour. What was her average rate of reading, in pages per hour?
(A) 60
(B) 70
(C) 48
(D) 50
Answer: (C) 48
Explanation: N/A
Q. 99
Ram aims to score an average of 80 marks in quarterly and half-yearly exams. But his average in quarterly is 3 marks less than his target and that in half-yearly is 2 marks more than his aim. The difference between the total marks scored in both the exams is 25. The total marks aimed by Ram is
(A) 400
(B) 410
(C) 420
(D) 380
Answer: (A) 400
Explanation: No. of exams in each of the quarterly and half-yearly exams be x (suppose)
Hence 82x – 77x = 25
hence x = 5
Marks aimed by Ram = 80 * 5 = 400
Q. 100
The average of marks scored by the students of a class is 68. The average of marks of the girls in the class is 80 and that of boys is 60. What is the percentage of boys in the class?
(A) 40%
(B) 60%
(C) 65 %
(D) 70 %
Answer: (B) 60%
Explanation: N/A