Averages Quiz Set 006

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Question 1

Two of the 32 numbers are 32 and 42, If these two are excluded the average of the remaining 30 numbers is 1 less than the average of all the 32 numbers. What is the average of all the 32 numbers?

 A

22.

 B

23.

 C

21.

 D

24.

Soln.
Ans: a

Let the required average be x. Then $32x - (32 + 42) = 30 × (x - 1).$ which gives $32x - 74 = 30 × (x - 1).$ Solving for x we get x = 22.


Question 2

What is the average of first 275 natural numbers?

 A

138.

 B

139.

 C

137.

 D

136.

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 = 275, we get average = 138.


Question 3

There are three sections in school with 40, 40 and 40 students respectively. The average weight of a student in these sections, respectively, is 3, 3 and 2 Kg. What is the average weight of all the the students of the combined sections?

 A

$2{2/3}$.

 B

$2{27/40}$.

 C

$2{79/120}$.

 D

$2{13/20}$.

Soln.
Ans: a

The sums of the weights of all the students is 40 × 3 + 40 × 3 + 40 × 2 = 320. The required average = 320/total students = $320/{40 + 40 + 40}$ = ${8/3}$, which is same as: $2{2/3}$.


Question 4

306 men and 204 women are employed in a farm. The average wage per person is Rs. 168. What is the wage of a man if women are paid Rs. 5 less?

 A

Rs. 170.

 B

Rs. 171.

 C

Rs. 169.

 D

Rs. 172.

Soln.
Ans: a

Let the wage of a man and a woman be x and x - 5. We are given the average ${x × 306 + (x - 5) × 204}/{306 + 204}$ = 168. This equation can be solved for x to get Rs. 170 as the answer.


Question 5

The average number of visitors at a zoo on a Monday is 156, whereas it is 162 on other days of the week. What will be the average number of visitors in a 30-day month that begins on a Monday?

 A

161.

 B

162.

 C

160.

 D

159.

Soln.
Ans: a

The month begins on a Monday, so there will be 5 Mondays. The average = ${5 × 156 + 25 × 162}/30$, which equals ${780 + 4050}/30$ = 161.


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This Blog Post/Article "Averages Quiz Set 006" 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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