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

The average marks of a student in 10 papers are 80. If the highest and the lowest scores are not considered, the average is 81. If his highest score is 92, what is the lowest score?

  1. 54

  2. 60

  3. 63

  4. 67

  5. Cannot be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total marks for 10 papers = 10 × 80 = 800. Excluding highest and lowest, average of 8 papers = 8 × 81 = 648. Sum of highest + lowest = 800 - 648 = 152. Given highest = 92, lowest = 152 - 92 = 60.

Multiple choice

The average marks of 40 students in an English exam is 72. Later it is found that three marks 64, 62 and 84 were wrongly entered as 68, 65 and 73. The average after mistakes were rectified is-
  1. $28.5$
  2. $28.65$
  3. $28.72$
  4. $28.80$

  5. None of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Total = 40 × 72 = 2880. Correction: 68 → 64 (-4), 65 → 62 (-3), 73 → 84 (+11). Net change = +4. Corrected total = 2884, corrected average = 2884/40 = 72.1. None of the options (28.5, 28.65, 28.72, 28.80) match.

Multiple choice

Average age of seven person in a group is 30 years, the average age of five person of this group is 31 years. What is the average age of the other two persons in the group?

  1. 15 years

  2. 26 years

  3. 55 years

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total age of 7 persons = 7 × 30 = 210 years. Total age of 5 persons = 5 × 31 = 155 years. Age of remaining 2 persons = 210 - 155 = 55 years. Average age of these 2 persons = 55/2 = 27.5 years. Since 27.5 years is not among options A, B, or C, the correct answer is 'None of these'.

Multiple choice

In an examination total marks of four subjects is 200. If the average of marks scored in three subjects is 48 then, what is the marks obtained in the fourth subject?

  1. 50

  2. 144

  3. 152

  4. 56
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Average of 3 subjects = 48, so sum of those 3 subjects = 48 × 3 = 144. Total marks for all 4 subjects = 200. Therefore, marks in fourth subject = 200 - 144 = 56. Option A (50) is incorrect. Option B (144) is the sum of three subjects, not the fourth.

Multiple choice

The question given below contain two statements giving certain data. You have to decide whether the data given in the statements are sufficient for answering the question? Mark answer- A certain amount of money is distributed among four persons A, B, C and D. The average amount each person got is Rs 10,000. How much did 'A' get? I. The sum of money A and B got together is Rs 35000. II. 'C got Rs 1000 less than what 'D' got.

  1. If statement I alone is sufficient but statement II alone is not sufficient.

  2. If statement II alone is sufficient but statement I alone is not sufficient.

  3. If each statement alone (either I or II) is sufficient.

  4. If statement I and II together are not sufficient.

  5. If both statement together is sufficient, but neither statement alone is sufficient.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total money = 4 × 10000 = 40000. Statement I: A + B = 35000 (insufficient alone). Statement II: C = D - 1000 (insufficient alone). Together: A + B + C + D = 40000 and C + D = 40000 - 35000 = 5000. From C = D - 1000 and C + D = 5000, we get C = 2000, D = 3000. But A + B = 35000 could be distributed in infinite ways (e.g., A=10000,B=25000 or A=15000,B=20000). Hence insufficient.

Multiple choice

A sum of money is distributed among four persons A, B, C and D. The average amount they get is Rs 6000. What is the amount 'C gets? I. 'A' and 'C' together get Rs 14000. II. 'B' gets Rs 3000 less then what 'C' gets.

  1. If statement I alone is sufficient but statement II alone is not sufficient.

  2. If statement II alone is sufficient but statement I alone is not sufficient.

  3. If each statement alone (either I or II) is sufficient.

  4. If statement I and II together are not sufficient.

  5. If both statement together is sufficient, but neither statement alone is sufficient.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total amount = 4 × 6000 = 24000. Statement I: A + C = 14000, which alone doesn't give C's value. Statement II: B = C - 3000, which alone doesn't give C. Combining: A + B + C + D = 24000, A + C = 14000, B = C - 3000. Substituting: 14000 + (C - 3000) + C + D = 24000, giving 2C + D = 13000. This has multiple solutions - if D = 0 then C = 6500, if D = 1000 then C = 6000. The value of C is not uniquely determined.

Multiple choice

The average weight of a group of 75 girls was calculated as 47 kgs. It was later discovered that the weight of one of the girls was read as 45 kgs., whereas her actual weight was 25 kgs. What is the actual average weight of the group of 75 girls? (Rounded off to two digits after decimal)
  1. $46.73 kgs.$
  2. $46.64 kgs.$
  3. $45.96 kgs.$
  4. $Can't be determined$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The recorded total was 75 × 47 = 3525 kg. The actual total should be 3525 - 45 + 25 = 3505 kg (subtracting the wrong reading and adding the correct weight). The actual average is 3505 ÷ 75 = 46.7333... kg, which rounds to 46.73 kg to two decimal places. The error was 20 kg (45 - 25), distributed over 75 girls, so each girl's average was off by 20/75 = 0.2667 kg.

Multiple choice

The average marks obtained by 15 students including (x) are 70 and the average marks obtained by 14 students excluding (x) is 68. What is the marks obtained by (x)?

  1. 78

  2. 98

  3. 88

  4. 90
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total marks for 15 students = 15 × 70 = 1050. Total marks for 14 students (excluding x) = 14 × 68 = 952. Therefore, marks obtained by x = 1050 - 952 = 98. This is a direct application of the average formula where x's marks represent the difference between the group totals.