Posted On:February 28, 2019, Posted By: Latest Interview Questions,
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Dear Readers, Welcome to __ Average - Aptitude Objective Questions__ have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of

1. Average = [Sum of observations / Number of observations]

2. Suppose a man covers a certain distance at x kmph and an equal distance at y kmph. Then, the average speed during the whole journey is [2xy / x + y] kmph.

Sol: There are five prime numbers between 30 and 50.

They are 31, 37, 41, 43 and 47.

=> Required average = [(31 + 37 + 41 + 43 + 47) / 5]

= 199/5

= 39.8.

Sol: Sum of first n natural numbers = 40 x 41 / 2

= 820.

=> Required average = 820 / 40

= 20.5.

Sol: Let the average after 17th inning = x.

Then, average after 16th inning = (x - 3)

=> 16(x - 3) + 87 = 17x or x = (87 - 48) = 39.

Sol: Number of boys = 136 x (5/2)

= 30,

Number of girls 6.

Average age of boys = (2 x 6)

= 12 years.

Total age of boys (30 x 12) years = 360 years.

Let the numbers are x, x+2, x+4 and x+6. Then,

(x+x+2+x+4+x+6)/4 = 27

=> 4x+ 12/4 = 27

=> x + 3 = 27

=> x = 24

Largest number = (x + 6) = 24 + 6 = 30.

A. 8 years

B. 12 years

C. 10 years

D. 14 years

Ans: B

**Explanation :**

Total age of 20 students = (30 x 12) - (5 x 10 + 5 x 14)= 240 years.

Required average = (240/20) = 12 years.

A. 4

B. 16

C. 8

D. Data inadequate

Ans: C

**Explanation :**

Total sum of remaining two (8 x 14 - 6 x 16) = 16.

Average of these two numbers = 16/2 = 8

A. 35

B. 37.5

C. 37

D. 40

Ans: B

**Explanation :**

Average speed = 2xy/(x + y) km/hr

= 2 x 50 x 30/(50 + 30)

= 37.5 km/hr

A. 90

B. 85

C. 110

D. 100

Ans: A

**Explanation :**

Sixth observation = [60 x 11 - (58 x 5 + 56 x 5)]

A. 3

B. 8

C. 6

D. 9

Ans: D

**Explanation :**

average = (1 + 2 + 3 + 4 + 5) x 3/5

= 15 x 3 / 5

= 9

A. 5(a + 4)

B. 5(a+b+c+d+e)

C. abcde

D. (a + 4)

Ans: D

**Explanation :**

Clearly,b=a+2,c=a+4,d=a+6 and e=a+8.

Average (a + (a + 2) + (a + 4) + (a + 6) + (a + 8)) / 5 = (5a + 20) / 5

= (a + 4)

A. 33.25

B. 33.5

C. 34.25

D. 35

Ans: C

**Explanation :**

Total sum of last 4 matches = (10 x 38.9) – (6 x 42)

= 389 - 252

= 137

Average = 137/4

= 34.25

A. 65

B. 69

C. 75

D. None of above

Ans: C

Explanation :

Average = (76+65+82+67+85 / 5 )

= 375 / 5

= 75

Hence average = 75

A. 21 years

B. 20 years

C. 18 years

D. 19 years

Ans: D

Explanation :

Total of the age of husband and wife = 2×23=46

Total of the age of husband and wife after 5 years + Age of the 1 year old child

= 46+5+5+1=57

Average age of the family = 57 / 3

= 19

A. 12.5 Yrs

B. 14.2 Yrs

C. 12.3 Yrs

D. 12.6 Yrs

E. None of these

Ans: D

Explanation :

Total age of 50 students

= (30X 13+20 X 12) = 630

Average = 630/50

= 12.6 Years

A. Rs. 2050

B. Rs. 2100

C. Rs. 1950

D. Rs. 2200

E. None of these

Ans: B

Explanation :

A. 42

B. 48

C. 44

D. 47

E. None of these

Ans: D

Explanation :

A. 25

B. 27

C. 30

D. 35

Ans: D

Explanation :

A. 1 year

B. 1.5 year

C. 2 year

D. 3 year

Ans: C

Explanation :

A. 53.33

B. 54.68

C. 55

D. None of these

Ans: B

Explanation :