Averages Quiz Set 013

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Question 1

The average age of three friends 3 years ago was 31 years. The average age of two them 5 years ago was 19 years. What is the present age of the third friend?

 A

54 years.

 B

55 years.

 C

53 years.

 D

52 years.

Soln.
Ans: a

Let the present ages of the three friends be a, b and c. We are given ${(b - 5) + (c - 5)}/2$ = 19. Which gives b + c = 48. We are also given ${(a - 3) + (b - 3) + (c - 3)}/3$ = 31, which gives a + b + c = 3 * 31 + 9 = 102. Putting b + c here we get a = 102 - (b + c) = 102 - 48 = 54 years.


Question 2

The average weight of the 12 bogies of a train increases by 9 Kg when a new bogie replaces a bogie of weight 12 Kg. What is the weight of the new bogie.

 A

120.

 B

121.

 C

119.

 D

122.

Soln.
Ans: a

The total increase of weight = 12 × 9 = 108. So the weight of the new bogie = 12 + 108 = 120 Kg.


Question 3

What is the average of first 263 natural numbers?

 A

132.

 B

133.

 C

131.

 D

130.

Soln.
Ans: a

The sum of first n natural numbers is $(n × (n + 1))/2$. The average is ${(n × (n + 1))/2}/n$ which is $(n + 1)/2.$ Putting n = 263, we get average = 132.


Question 4

Each of the 4 bulbs of a batch has a life 81 years. If a new bulb with a life 44 years more than the average of all 5 bulbs is added, what is the sum total of the values of all 5 bulbs?

 A

460 years.

 B

461 years.

 C

459 years.

 D

458 years.

Soln.
Ans: a

Let the average of all 5 bulbs be x, then the required total is T = 5x. By averages, $x = {4 × 81 + (x + 44)}/5$ which is same as $x × 5 = {4 × 81 + (x + 44)}$, which is same as $T = {4 × 81 + (T/5 + 44)}$, solving for T we get 460 years.


Question 5

The sales(in rupees) of a karyana store for five consecutive days is 1770, 1086, 2220, 3774, 2154. What should be the sale on the sixth day so that the overall average sale is 1966?

 A

Rs.792.

 B

Rs.798.

 C

Rs.786.

 D

Rs.804.

Soln.
Ans: a

The total sale on first five days is 1770 + 1086 + 2220 + 3774 + 2154 = 11004. Let the sale on 6th day be x. The average for 6 days is: 1966 = ${11004 + x}/6$ which gives x = $6 × 1966 - 11004$ = Rs. 792.


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Creative Commons License
This Blog Post/Article "Averages Quiz Set 013" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2019-08-18.

Posted by Parveen(Hoven),
Aptitude Trainer


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