Averages Quiz Set 002

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Question 1

Average weight of a group of 25 boys is 46 Kg. Later it was found that the weighing machine was showing 3 Kg more than the actual weight. What is the actual average weight?

 A

43.

 B

44.

 C

42.

 D

41.

Soln.
Ans: a

Let the total weight of the group as measured with the faulty machine be x. Then, by average formula $46 = x/25$, which gives x = $46 × 25 = 1150$. When weight of each of the 25 boys is reduced by 3 Kg, the new total becomes $1150 - 25 × 3 = 1075$, the new average becomes $1075/25 = 43$. TIP: As a shortcut, the new average = old average - error in weighing machine.


Question 2

The average weight of 13 students of a class is 39 Kg, whereas the average weight of remaining 17 students is 30 Kg. What is the average weight of all 30 students?

 A

$33{9/10}$.

 B

$35{2/29}$.

 C

$32{25/31}$.

 D

$36{9/28}$.

Soln.
Ans: a

Total weight of 13 students is 13 × 39 = 507. Similarly, the total weight of remaining 17 students is 17 × 30 = 510. The total weight of all 30 students is 507 + 510 = 1017. So the average = 1017/30 = $33{9/10}$.


Question 3

The average age of three friends 3 years ago was 30 years. The average age of two them 5 years ago was 13 years. What is the present age of the third friend?

 A

63 years.

 B

64 years.

 C

62 years.

 D

61 years.

Soln.
Ans: a

Let the present ages of the three friends be a, b and c. We are given ${(b - 5) + (c - 5)}/2$ = 13. Which gives b + c = 36. We are also given ${(a - 3) + (b - 3) + (c - 3)}/3$ = 30, which gives a + b + c = 3 * 30 + 9 = 99. Putting b + c here we get a = 99 - (b + c) = 99 - 36 = 63 years.


Question 4

The sales(in rupees) of a karyana store for five consecutive days is 4392, 5040, 3630, 1554, 612. What should be the sale on the sixth day so that the overall average sale is 3179?

 A

Rs.3846.

 B

Rs.3852.

 C

Rs.3840.

 D

Rs.3858.

Soln.
Ans: a

The total sale on first five days is 4392 + 5040 + 3630 + 1554 + 612 = 15228. Let the sale on 6th day be x. The average for 6 days is: 3179 = ${15228 + x}/6$ which gives x = $6 × 3179 - 15228$ = Rs. 3846.


Question 5

Each of the 5 boys of a class has a weight 60 Kg. If a new boy with a weight 55 Kg more than the average of all 6 boys is added, what is the sum total of the values of all 6 boys?

 A

426 Kg.

 B

427 Kg.

 C

425 Kg.

 D

424 Kg.

Soln.
Ans: a

Let the average of all 6 boys be x, then the required total is T = 6x. By averages, $x = {5 × 60 + (x + 55)}/6$ which is same as $x × 6 = {5 × 60 + (x + 55)}$, which is same as $T = {5 × 60 + (T/6 + 55)}$, solving for T we get 426 Kg.


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Creative Commons License
This Blog Post/Article "Averages Quiz Set 002" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-06-24.

Posted by Parveen(Hoven),
Aptitude Trainer


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