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Free Averages MCQs with Answers

90 Averages MCQs from Mathematics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

An average represents the total of a set of values divided by the number of values, and a weighted average gives different importance to different groups. Problems involve missing values, combined averages, replacement of observations, and changes in the average, so the total and count must be tracked separately.

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61. The average of 35 numbers is 25. If each number is multiplied by 5, find the new average?

  • A. 125
  • B. 134
  • C. 170
  • D. 98

Explanation: When every number is multiplied by 5, the average is also multiplied by 5 because the total is multiplied by 5 while the number of terms…

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Correct answer: 125

62. The average salary of a person for the months of January, February, March and April is Rs.8000 and that for the months February, March, April and May is Rs.8500. If his salary for the month of May is Rs.6500, find his salary for the month of January?

  • A. 3000
  • B. 2500
  • C. 4500
  • D. 5000

Explanation: The January-to-April salary total is 4 x Rs. 8000 = Rs. 32,000, while the February-to-May total is 4 x Rs. 8500 = Rs. 34,000.

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Correct answer: 4500

63. The average marks of a class of 30 students is 40 and that of another class of 50 students is 60. Find the average marks of all the students?

  • A. 50
  • B. 47.5
  • C. 59
  • D. 52.5

Explanation: The first class has total marks 30 x 40 = 1200 marks, and the second has 50 x 60 = 3000 marks.

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Correct answer: 52.5

64. A batsman makes a score of 64 runs in the 16th innings and thus increased his average by 3. Find his average after the 16th inning?

  • A. 17
  • B. 29
  • C. 18
  • D. 19

Explanation: Let the average after 15 innings be x runs. Then the total before the 16th innings is 15x runs, and after scoring 64 runs the new average…

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Correct answer: 19

65. Find the average of the first 20 natural numbers?

  • A. 10
  • B. 11.5
  • C. 12
  • D. 10.5

Explanation: The first 20 natural numbers are 1 through 20, whose average is the midpoint of the first and last terms: (1 + 20) / 2 = 10.5.

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Correct answer: 10.5

66. The average of 11 results is 50, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?

  • A. 46
  • B. 56
  • C. 34
  • D. 57

Explanation: The total of 11 results is 11 x 50 = 550, while the first six total 6 x 49 = 294 and the last six total 6 x 52 = 312.

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Correct answer: 56

67. The average of five results is 46 and that of the first four is 45. The fifth result is__________?

  • A. 1
  • B. 10
  • C. 12.5
  • D. 50

Explanation: The five results total 5 x 46 = 230, and the first four total 4 x 45 = 180. Therefore the fifth result is 230 - 180 = 50.

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Correct answer: 50

68. Three years ago the average age of a family of six members was 19 years. A boy have been born, the average age of the family is the same today. What is the age of the boy?

  • A. 1 year
  • B. 1.5 years
  • C. 2 years
  • D. 2.5 years

Explanation: Three years ago, the six family members had a total age of 6 x 19 = 114 years.

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Correct answer: 1 year

69. The average weight of 25 persons sitting in a boat had some value. A new person added to them whose weight was 46 kg only. Due to his arrival, the average weight of all the persons decreased by 5 kg. Find the average weight of first 25 persons?

  • A. 55 kg
  • B. 62 kg
  • C. 56 kg
  • D. None

Explanation: Let the original average be x kg, so the 25-person total is 25x kg. After adding a 46 kg person, the 26-person average is x - 5 kg, giving…

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Correct answer: None

70. The average marks in mathematics scored by the students of a school at the public examination were 39. If four of these students who actually scored 5, 12, 15 and 19 marks at the examination had not been sent up, the average marks for the school would have been 44. Find the number of students sent up for examination from the school?

  • A. 20
  • B. 25
  • C. 30
  • D. 32

Explanation: If n students were sent up, their total marks were 39n marks. Removing four students removes 5 + 12 + 15 + 19 = 51 marks, and the…

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Correct answer: 25

71. Nine men went to a hotel. Eight of them spent Rs.3 each over their meals and the ninth spent Rs.2 more than the average expenditure of all the nine. Determine the total money spent by them?

  • A. Rs.29.25
  • B. Rs.30.25
  • C. Rs.32
  • D. Rs.35

Explanation: Let the ninth person's expenditure be x rupees. Since it is Rs.2 more than the average, x = (24 + x)/9 + 2, giving 9x = 24 + x + 18, so x…

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Correct answer: Rs.29.25

72. The average age 9 members of a committee are the same as it was 2 years ago, because an old number has been replaced by a younger number. Find how much younger is the new member than the old number?

  • A. 7 years
  • B. 11 years
  • C. 18 years
  • D. 27 years

Explanation: In 2 years, the ages of 9 members would increase by 9 x 2 = 18 years in total.

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Correct answer: 18 years

73. The average temperature for Monday, Tuesday, Wednesday and Thursday was 48 degrees and for Tuesday, Wednesday, Thursday and Friday was 46 degrees. If the temperature on Monday was 42 degrees. Find the temperature on Friday?

  • A. 40 degrees
  • B. 38 degrees
  • C. 36 degrees
  • D. 34 degrees

Explanation: The Monday-to-Thursday total is 4 x 48 = 192 degrees, while the Tuesday-to-Friday total is 4 x 46 = 184 degrees.

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Correct answer: 34 degrees

74. A building contractor employs 20 male, 15 female and 5 child workers. To a male worker he pays Rs.25 per day, to a female worker Rs.20 per day and a child worker Rs.8 per day. The average wage per day paid by the contractor is__________?

  • A. Rs.20
  • B. Rs.21
  • C. Rs.22
  • D. Rs.23

Explanation: The total daily wages are 20 x Rs.25 + 15 x Rs.20 + 5 x Rs.8 = Rs.840. There are 20 + 15 + 5 = 40 workers, so the average wage is…

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Correct answer: Rs.21

75. Visitors to show were charged Rs.15 each on the first day. Rs.7.50 on the second day, Rs.2.50 on the third day and total attendance on the three days were in ratio 2:5:13 respectively. The average charge per person for the whole show is___________?

  • A. Rs.3
  • B. Rs.4.50
  • C. Rs.5.00
  • D. Rs.7.50

Explanation: Take the attendance numbers as 2, 5 and 13 units, so total attendance is 20 units.

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Correct answer: Rs.5.00

76. In a hostel there were 100 students. To accommodate 20 more students the average is decreased by rupees 5. But total expenditure increased by Rs.400. Find the total expenditure of the hostel now?

  • A. Rs.5000
  • B. Rs.4600
  • C. Rs.5400
  • D. Rs.2300

Explanation: Let the original average expenditure be Rs.x, so the original total is Rs.100x.

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Correct answer: Rs.5400

77. A batsman in his 17th innings makes a score of 85 and their by increasing his average by 3. What is his average after the 17th innings?

  • A. 34
  • B. 35
  • C. 36
  • D. 37Computer Online Quiz

Explanation: Let the average after 16 innings be x runs, so the previous total score was 16x runs.

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Correct answer: 37Computer Online Quiz

78. The average age of a husband and a wife is 23 years when they were married five years ago but now the average age of the husband, wife and child is 20 years(the child was born during the interval). What is the present age of the child?

  • A. 1 year
  • B. 2 years
  • C. 3 years
  • D. 4 years

Explanation: Five years ago, the couple's combined age was 2 x 23 = 46 years. In five years their combined present age becomes 46 + 2 x 5 = 56 years…

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Correct answer: 4 years

79. The average age of M boys is 'b' years and of 'n' girls 'c' years. The average age of all together is_________?

  • A. (mb - nc)/ (m + n) years
  • B. (mb + nc)/ (m - n) years
  • C. (mb + nc)/ (m + n) years
  • D. (mb - nc)/ (m - n) years

Explanation: The total age of the M boys is Mb years, and the total age of the n girls is nc years.

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Correct answer: (mb + nc)/ (m + n) years

80. A team of eight entered for a shooting competition. The best marks man scored 85 points. If he had scored 92 points, the average scores for. The team would have been 84. How many points altogether did the team score?

  • A. 625
  • B. 665
  • C. 632
  • D. 656

Explanation: If the best marksman had scored 92 points, the team's total would have been 8 x 84 = 672 points.

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Correct answer: 665
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