Quantitative Aptitude

Averages

1,527 Questions
All Basic average and reverse calculation 405 Adding or removing an observation 342 Weighted and combined averages 320 Replacement and correction of a recorded value 233 Ratio shortcut for two-group mixtures 111 Equal-distance average speed 59 Age, score, weight, and spending applications 32 Consecutive terms and arithmetic progressions 25

Averages Questions

Multiple choice

Amazon, a company, organized a hiring event in which it invited all eligible candidates to take an exam. If the average marks of the candidates who took the exam were 64, the top 15% scorers had an average of 90 marks and the dullest 20% had an average marks of 28, then what was the average score of the remaining 65% of the candidates?

  1. 69.07

  2. 65.25

  3. 62.31

  4. 60.08

  5. 58.77
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total sum = 100 * 64 = 6400. Top 15% sum = 15 * 90 = 1350. Dullest 20% sum = 20 * 28 = 560. Remaining 65% sum = 6400 - 1350 - 560 = 4490. Average = 4490 / 65 = 69.0769.

Multiple choice

Eddison owns a shop and sells various items. He sells a carton of Oreo biscuits for \$40 and a carton of Jim-Jam biscuits for \$60. Alfie buys a total of 10 cartons of both Oreo and Jim-Jam biscuits from Eddison's shop, and the average price at which he buys 10 cartons is \$56. However, to reduce the average price, he now plans to buy fewer cartons of Jim-Jam biscuits but the same number of cartons of Oreo biscuits. How many fewer cartons of Jim-Jam biscuits should he buy so that the average price of cartons is \$52?

  1. 3

  2. 4

  3. 5

  4. 6

  5. 7
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Initial cost: 10 cartons, average $56, total $560. Let O be Oreo and J be Jim-Jam. 40O + 60J = 560 and O + J = 10. Solving gives O=2, J=8. New target: average $52 for O + J_new = 10 - x. 40(2) + 60(8-x) = 52(10-x). 80 + 480 - 60x = 520 - 52x. 40 = 8x. x=5.

Multiple choice

In a society, there were a total of ten families. A survey was conducted, and it was found out that the average spending of all those ten families on a yearly basis was \$35,000. If six out of the ten families had an average spending of \$40,000 each, then what was the average spending of the other four families on a yearly basis?
  1. $25,000
  2. $27,500
  3. $30,000
  4. $32,500
  5. $35,000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total spending = 10 * 35,000 = 350,000. Spending of 6 families = 6 * 40,000 = 240,000. Remaining spending = 350,000 - 240,000 = 110,000. Average of 4 families = 110,000 / 4 = 27,500.

Multiple choice

In a society, there were a total of 14 people, who worked as teachers, and 10 people, who worked as sales representatives. The total average of the number of tasks done by them was 31. If the average number of tasks done by the teachers was 36, then what was the average number of tasks done by the sales representatives?

  1. 24

  2. 25

  3. 26

  4. 27

  5. 28
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total tasks = (14 * 36) + (10 * S) = (14 + 10) * 31. 504 + 10S = 744. 10S = 240, so S = 24.

Multiple choice

Freddy was preparing for an exam and he used to take practice mocks. His average marks were 20. He took another mock and got 25 marks, and then his average increased to 21 marks per mock. How many mocks did he attempt before the mock in which he scored 25 marks?

  1. 2

  2. 3

  3. 4

  4. 5

  5. 6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let n be the number of mocks before the last one. Total marks = 20n. After the new mock, total marks = 20n + 25, and the new average is 21 for n+1 mocks. So, (20n + 25) / (n + 1) = 21, which leads to 20n + 25 = 21n + 21, so n = 4.

Multiple choice

The average number of marks scored by a person in subjects A, B and C was 82. The ratio of marks scored by him in subjects A and B was 3 : 4 and in subjects B and C was 3 : 5, respectively. Find the difference between the marks scored by him in subjects B and C.

  1. 36

  2. 42

  3. 48

  4. 54

  5. 60
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given A:B = 3:4 and B:C = 3:5, we find the combined ratio A:B:C = 9:12:20. The sum of parts is 41. Average of 82 means total marks = 246. Each part is 246 / 41 = 6. Marks for B = 12 * 6 = 72, marks for C = 20 * 6 = 120. Difference = 120 - 72 = 48.

Multiple choice

The number of students in section A and section B of a class are 40 and 52, respectively. The average score in mathematics of all the students is 75. If the average score of the students in A is 20% more than that of students in B, then what is the average score of students in B?

  1. 71

  2. 65

  3. 69

  4. 63
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let average of B be x. Average of A = 1.2x. Total sum = 40 * 1.2x + 52 * x = 92 * 75. 48x + 52x = 6900. 100x = 6900, x = 69.