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

How many marked did Tarun secure in English? I. The average mark obtained by Tarun in four subjects including English is $60$. II. The total marks obtained by him in English and Mathematics together are $170$. III. The total marks obtained by him in Mathematics and Science together are $180$.

  1. I and II only

  2. II and III only

  3. I and III only

  4. All I, II and III

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

We have 4 subjects. Let marks be E, M, S, O. I: E+M+S+O = 240. II: E+M = 170. III: M+S = 180. We have 3 equations but 4 variables (E, M, S, O). We cannot isolate E without knowing O or S individually.

Multiple choice

The average weight of three men $'X', 'Y'$ and $'Z'$ is $75$ kgs. Another mand $'A'$ joins the group and the average weight now becomes $80\ kgs$. If another person $'B'$ whose weight is $5\ kgs$ more than $'A$ replaces $'X'$, then the average weight of $'Y', 'Z', 'A'$ and $'B'$ will be $85\ kgs$. What is the weight of $'X'$?
  1. $84\ kgs$
  2. $82\ kgs$
  3. $78\ kgs$
  4. $80\ kgs$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The total weight of X, Y, and Z is 3 x 75 = 225 kg. After A joins, the total is 4 x 80 = 320 kg, so A weighs 95 kg and B weighs 100 kg. The final total is 4 x 85 = 340 kg, giving X = 225 - (340 - 95 - 100) = 80 kg.

Multiple choice

A person purchases one kg of tomatoes from each of the $4$ places at the rate of 1 kg, 2 kg, 3 kg , 4 kg per rupee respectively. On the average he has purchased $x$ kg of tomatoes per rupee, then the value of x is
  1. $2$
  2. $2.5$
  3. $1.92$

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

Total quantity = 1+1+1+1 = 4 kg. Total cost = 1/1 + 1/2 + 1/3 + 1/4 = (12+6+4+3)/12 = 25/12 rupees. Average = Total quantity / Total cost = 4 / (25/12) = 48/25 = 1.92 kg per rupee.