Aptitude - Averages Online Quiz


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Following quiz provides Multiple Choice Questions (MCQs) related to Averages. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - 25 is the average of these number which are 40, 10, 25, 20, 35, x . find out the value of x?

A - 34

B - 20

C - 37

D - 45

Answer : B

Explanation

(40+10+25+20+35+x)/6 = 25 ⇒  130+x = 150 = x = 20

Q 2 - 28 is the average of 3 numbers. Find out the value of third number if the given condition is such that the second number have the double value in the comparison of first number and third number have 4 times value of first number?

A - 48

B - 34

C - 22

D - 21

Answer : A

Explanation

If x is the value of third number.
Then  the value of second number is x/2 , if x/2 is the value of second number then the value of first number will be 1/2 . x/2 = x/4.
Total sum of three number = (3*28) =84
∴ x+x/2+x/4 = 84 ⇒ 7x/4 = 84 ⇒ x= (84*4)/7 = 48
So, its proves that the value of the third number is 48.

Q 3 - A class has 24 students. If 18 year old boys left the school and one new boy join the school in that situation the average decrease by 1 month. Find out the age of new boy?

A - 16 years

B - 17 years

C - 25 years

D - 23 years

Answer : A

Explanation

Downfall in the total age =( 24*1 )= 24 months =2 years
The age of the new boy = 18- 2 = 16 years.

Q 4 - Find out the average speed of the journey if with the speed of 6km/hr covers half distance and remaining half covers by the speed of 3 km/hr.

A - 5 km/hr

B - 4 km/hr

C - 3 km/hr

D - 2 km/hr

Answer : B

Explanation

Average speed = 2xy / (x+y)km/hr = 2*6*3/ (6+3)km/hr = 4km/hr 

Q 5 - What should be the average of monthly consumption if 110 ltr is the average of 7 month and Rs. 86 is the average for the next 5 month consumption?

A - 26 ltr

B - 34 ltr

C - 70 ltr

D - 100 ltr

Answer : D

Explanation

12 month consumptions = [(110*7)+(86*5)] ltr. = 1200 ltr.
∴ per month consumption = 1200/12 = 100 ltr.

Q 6 - Find out the original average weight of the class if 1 kg weight increased in average weight if we add a new person who has 50 kg. If one more add in the class then the average weight increased with 1.5 kg over the original average.

A - 47 kg

B - 36 kg

C - 26 kg

D - 52 kg

Answer : A

Explanation

if x is the average the number of students and y is the average weight.
Then ,   xy+50/ (x+1) =(y+1) ⇒ xy+50=  xy+x+y+1 ⇒ x+y= 49...(i)
xy+50+50/(x+2) = (y+3/2 )⇒ xy+100 = xy +3x/2+2y+3
⇒  3x/2+ 2y = 97 ⇒ 3x+4y =194 ...(ii)
Multiplying (i) by 3 and subtracting it from (iii), we get y =47.
Hence , the original average of weight is 47 kg.

Q 7 - The average score of a cricketer for ten matches is 38.9 runs. If the average for the first six matches is 42, then find the average for the last four matches?

A - 33.25

B - 34.25

C - 33.5

D - 35

Answer - B

Explanation

Required average = (38.9 x 10) - (42 x 6)4 = 1374 = 34.25.

Q 8 - If the arithmetic mean of seventy-five numbers is calculated, it is 35. If each number is increased by 5, then mean of new number is?

A - 70

B - 90

C - 30

D - 40

Answer - D

Explanation

A.M. of 75 numbers = 35. 
Sum of 75 numbers = (75 x 35) = 2625. 
Total increase = (75 x 5) = 375. 
Increased sum = (2625 + 375) = 3000. 
Increased average = 300075 = 40.

Q 9 - The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400g. The weight of the teacher is:?

A - 50

B - 45

C - 53

D - 55

Answer - B

Explanation

Weight of the teacher = (35.4 x 25 - 35 x 24)kg = 45 kg

Q 10 - The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is?

A - 5:4

B - 2:3

C - 1:2

D - 3:4

Answer - B

Explanation

Let the ratio be k : 1. then, 
k x 16.4 + 1 x 15.4 = (k + 1) x 15.8 
(16.4 - 15.8) k = (15.8 - 15.4) 

k = 0.40.6 = 23
aptitude_averages.htm
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