Averages Quiz Set 002

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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 12 years. What is the present age of the third friend?

 A

68 years.

 B

69 years.

 C

67 years.

 D

66 years.

Soln.
Ans: a

Let the present ages of the three friends be a, b and c. We are given ${(b - 5) + (c - 5)}/2$ = 12. Which gives b + c = 34. 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 - 34 = 68 years.


Question 2

What is the average of first 383 natural numbers?

 A

192.

 B

193.

 C

191.

 D

190.

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 = 383, we get average = 192.


Question 3

Average marks of class of 10 students is 62. What will be the average if each student is given 8 as grace marks?

 A

70.

 B

71.

 C

69.

 D

68.

Soln.
Ans: a

Let the total score of the class before grace marks be x. Then, by average formula $62 = x/10$, which gives x = $62 × 10 = 620$. When grace marks = 8 are added for each of the 10 students, the new total becomes $620 + 10 × 8 = 700$, the new average becomes $700/10 = 70$. TIP: As a shortcut, the new average = old average + grace marks.


Question 4

412 men and 103 women are employed in a farm. The average wage per person is Rs. 194. What is the wage of a man if women are paid Rs. 5 less?

 A

Rs. 195.

 B

Rs. 196.

 C

Rs. 194.

 D

Rs. 197.

Soln.
Ans: a

Let the wage of a man and a woman be x and x - 5. We are given the average ${x × 412 + (x - 5) × 103}/{412 + 103}$ = 194. This equation can be solved for x to get Rs. 195 as the answer.


Question 5

154 men and 616 women are employed in a farm. The average wage per person is Rs. 141. What is the wage of a man if women are paid Rs. 5 less?

 A

Rs. 145.

 B

Rs. 146.

 C

Rs. 144.

 D

Rs. 147.

Soln.
Ans: a

Let the wage of a man and a woman be x and x - 5. We are given the average ${x × 154 + (x - 5) × 616}/{154 + 616}$ = 141. This equation can be solved for x to get Rs. 145 as the answer.


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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 2017-05-17.

Posted by Parveen(Hoven),
Aptitude Trainer


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