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 - Find out the average of A and B if the given value of 16A+ 16B = 48

A - 1.5

B - 2

C - 5.3

D - 7.4

Answer : A

Explanation

16a+16b = 48 ⇒ 16(a+b) = 48 ⇒ (a+b) = 3
So, we  have a and b average  is  (a+b)/2 = 3/2 = 1.5

Q 2 - 15 year is the average age of 24 boys and their teacher also. The average became 14 years if we leave the teacher age. In that case what should be the age of teacher?

A - 67 years

B - 34 years

C - 45 years

D - 39 years

Answer : D

Explanation

24 boys and 1 teacher have sum of the ages= (15*25) =375 years
24 boys have the sum of the ages =  (24*14) =336 years.
Its proves that the age of the teacher =  (375- 336)= 39 years.

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 - 42 years is the average age of father, mother and son age. After the marriage of son, a child was born. 36 year is the average age of the family if at that time the child age is 5 year. Find out the age of the daughter in law at the marriage time?

A - 25 years

B - 27 years

C - 31 years

D - 26 years

Answer : A

Explanation

At the time of son marriage, H+W+S =(42*3)=126 and let the age of daughter in law be D years.
After the marriage of the 6 year :
126+(6*3)+5+(D+6) =(36*5) ⇒ 155+D = 180
⇒ D =(180- 155) = 25
AT the time of marriage , age of daughter in law = 25 years.

Q 5 - What should be the the first number if we have four numbers and given condition is that 15 is the average of first three number and last three number have 16 average if 19 is the last number given?

A - 16

B - 45

C - 26

D - 23

Answer : A

Explanation

let the numbers be x, x1,x2,x3,x4 ,then ,
x1+x2+x3 =(15*3)= 45
x2+x3+x4 =(16*3)= 48
On subtracting ,we get x4-x1=3
∴19-x1 =3 ⇒ x1=16.
First number = 16

Q 6 - M is the average of 5 consecutive natural numbers. What should be the improvement in average if next 3 numbers included?

A - 1

B - 1.5

C - 1.4

D - 2

Answer : B

Explanation

let the 5 consecutive natural numbers be n, n+1,n+2, n+3, n+4. Then
n+(n+1)+(n+2)+(n+3)+(n+4) /5 = 5n+10= 5m ⇒ 5(n+2)= 5m  ⇒ (n+2) =m ⇒ n=(m-2)
New numbers are m-2, m-1, m, m+1,m+2,m +3, m+4, m+5
New average = ( 8m+12)/8 = m+1.5 , which is 1.5 more than m.

Q 7 - The average of six numbers is 3.95. The average of two of them is 3.4, while the average of the other two is 3.85. What is the average of the remaining two numbers?

A - 4.5

B - 4.6

C - 4.7

D - 4.8

Answer - B

Explanation

Sum of the remaining two numbers = (3.95 x 6) - [(3.4 x 2) + (3.85 x 2)] = 23.70 - (6.8 + 7.7) = 23.70 - 14.5 = 9.20 
Therefore Required average = 9.22 = 4.6.

Q 8 - A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is?

A - 20

B - 73

C - 40

D - 10

Answer - D

Explanation

Let there be z pupils in the class. 
Total increase in marks = z x 12 = z2 
Therefore z2 = (83 - 63) = z2 = 20 z = 40.

Q 9 - A cricketer has a certain average for 10 innings. In the eleventh inning, he scored 108 runs, thereby increasing his average by 6 runs. His new average is?

A - 52

B - 48

C - 55

D - 60

Answer - B

Explanation

Let average for 10 innings be z. Then, 
= 10z + 10811 = 11z + 66 = 10z + 108 = z = 42. 

New average = (z + 6) = 48 runs.

Q 10 - 3 years ago. the average age of a family of 5 members was 17 years. A baby having been born, the average age of the family is the same today. The present age of the baby is ?

A - 3

B - 4

C - 2

D - 1

Answer - C

Explanation

Total age of 5 members, 3 years ago = (17 x 5) years = 85 years 
Total age of 5 members now = (85 + 3 x 5) yrs = 100 years 
Total age of 6 members now = (17 x 6) years = 102 years 

Therefore Age of younger child = (102 - 100) = 2 years

aptitude_averages.htm

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