RRB NTPC - Averages (200 Questions with Explanation): Quantitative Aptitude Test

  • 1. Average of 13 results is 65. If the average of first six results is 61 and average of last six results is 59 Then find the seventh result?
   A.) 115
   B.) 135
   C.) 125
   D.) 105

Answer: Option 'C'

125

  • 2. Average of 13 results is 65. If the average of first six results is 61 and average of last six results is 59 Then find the seventh result?
   A.) 115
   B.) 135
   C.) 125
   D.) 105

Answer: Option 'C'

125

  • 3. The average weight of a class of 20 boys was calculated to be 58.4 kgs and it was later found that one weight was misread as 56 kg instead of 65 kg. What is the correct weight? 
   A.) 67.4kg
   B.) 57.75kg
   C.) 58.85kg
   D.) 49.4kg

Answer: Option 'C'

Actual total weight is (20 × 58.4 - 56 + 65) = 1177 Kgs
Actual average weight is 1177/20 = 58.85kgs

  • 4. The average weight of a class of 20 boys was calculated to be 58.4 kgs and it was later found that one weight was misread as 56 kg instead of 65 kg. What is the correct weight? 
   A.) 67.4kg
   B.) 57.75kg
   C.) 58.85kg
   D.) 49.4kg

Answer: Option 'C'

Actual total weight is (20 × 58.4 - 56 + 65) = 1177 Kgs
Actual average weight is 1177/20 = 58.85kgs

  • 5. The average of 10 numbers is 25. The average of first three numbers is 22 1/3 and that of next five is 15 1/5. If the eighth be less than the ninth and tenth numbers by 5 and 11 respectively, then the tenth number is:
   A.) 29
   B.) 21
   C.) 41
   D.) 30

Answer: Option 'C'

41

  • 6. The average of 10 numbers is 25. The average of first three numbers is 22 1/3 and that of next five is 15 1/5. If the eighth be less than the ninth and tenth numbers by 5 and 11 respectively, then the tenth number is:
   A.) 29
   B.) 21
   C.) 41
   D.) 30

Answer: Option 'C'

41

  • 7. The average of 5 consecutive numbers is n. if the next two number are also included. The average will? 
   A.) Remain the same
   B.) Increase by 1
   C.) Increase by 2
   D.) Decrease by 1

Answer: Option 'B'

Increase by 1

  • 8. The average of 5 consecutive numbers is n. if the next two number are also included. The average will? 
   A.) Remain the same
   B.) Increase by 1
   C.) Increase by 2
   D.) Decrease by 1

Answer: Option 'B'

Increase by 1

  • 9. The average of marks of a student of 8 exams was 35. How many marks must be get in the next exam so as to increase his average of marks by 5?
   A.) 75
   B.) 80
   C.) 83
   D.) 79

Answer: Option 'B'

80

  • 10. The average of marks of a student of 8 exams was 35. How many marks must be get in the next exam so as to increase his average of marks by 5?
   A.) 75
   B.) 80
   C.) 83
   D.) 79

Answer: Option 'B'

80

  • 11. If the average age of six numbers is 30. If one is excluded. The average become 25. The excluded number is:
   A.) 54
   B.) 55
   C.) 53
   D.) 45

Answer: Option 'B'

  • 12. If the average age of six numbers is 30. If one is excluded. The average become 25. The excluded number is:
   A.) 54
   B.) 55
   C.) 53
   D.) 45

Answer: Option 'B'

  • 13. Of the three numbers whose average is 45, the first is half of the sum of the others. The first number is: 
   A.) 45
   B.) 51
   C.) 59
   D.) 49

Answer: Option 'A'

45

  • 14. Of the three numbers whose average is 45, the first is half of the sum of the others. The first number is: 
   A.) 45
   B.) 51
   C.) 59
   D.) 49

Answer: Option 'A'

45

  • 15. The average age of father and his two sons is 27 Years. Five years ago, the average age of the two sons was 12 Years. If the difference between the ages of the two sons is four years, what is the present age of the father? 
   A.) 42
   B.) 47
   C.) 48
   D.) 49

Answer: Option 'B'

The total present age of father and two sons is 3S27 = 81 yrs
The total present age of sons is (12+5) X 2 = 34Years
so, present age of father is 81 - 34 = 47 yrs

  • 16. The average age of father and his two sons is 27 Years. Five years ago, the average age of the two sons was 12 Years. If the difference between the ages of the two sons is four years, what is the present age of the father? 
   A.) 42
   B.) 47
   C.) 48
   D.) 49

Answer: Option 'B'

The total present age of father and two sons is 3S27 = 81 yrs
The total present age of sons is (12+5) X 2 = 34Years
so, present age of father is 81 - 34 = 47 yrs

  • 17. There were 45 students in a hostel, if the numbers of students increased by 7, the expenses of the mess were increased by Rs. 39 per day while the average expenditure per head diminished by Re.1. What is the original expenditure of the mess? 
   A.) Rs. 562
   B.) Rs. 624
   C.) Rs. 1950
   D.) Rs. 585

Answer: Option 'D'

Let the original expenditure be Rs.x
Original average expenditure = X/45
New average expenditure = (x+39)/52
So (x/45) - ((x+39) / 52) = 1  so x = 585
so, original expenditure is Rs 585

  • 18. There were 45 students in a hostel, if the numbers of students increased by 7, the expenses of the mess were increased by Rs. 39 per day while the average expenditure per head diminished by Re.1. What is the original expenditure of the mess? 
   A.) Rs. 562
   B.) Rs. 624
   C.) Rs. 1950
   D.) Rs. 585

Answer: Option 'D'

Let the original expenditure be Rs.x
Original average expenditure = X/45
New average expenditure = (x+39)/52
So (x/45) - ((x+39) / 52) = 1  so x = 585
so, original expenditure is Rs 585

  • 19. Of three numbers, the third is twice the second and the second is 4 times the first. If their average is 78, the smallest of the three numbers is: 
   A.) 15
   B.) 21
   C.) 17
   D.) 18

Answer: Option 'D'

Let first number be x. 
So,2nd no. = 4x & 3rd no.=8x.
So,x+4x+8x=78 × 3 = 234.
13x = 234 
x = 234/13 
Hence,smallest Number x=18.

  • 20. Of three numbers, the third is twice the second and the second is 4 times the first. If their average is 78, the smallest of the three numbers is: 
   A.) 15
   B.) 21
   C.) 17
   D.) 18

Answer: Option 'D'

Let first number be x. 
So,2nd no. = 4x & 3rd no.=8x.
So,x+4x+8x=78 × 3 = 234.
13x = 234 
x = 234/13 
Hence,smallest Number x=18.

  • 21. If the average of seven numbers is 35. If one is included. The average become 40. The included number is: 
   A.) 70
   B.) 75
   C.) 65
   D.) 80

Answer: Option 'B'

75

  • 22. If the average of seven numbers is 35. If one is included. The average become 40. The included number is: 
   A.) 70
   B.) 75
   C.) 65
   D.) 80

Answer: Option 'B'

75

  • 23. Out of 12 employs of a bank, one employ retires and his place, a new employ of age 24 years joins as a result average age of employs reduces by 4 years. The age of the retired employ is: 
   A.) 72
   B.) 62
   C.) 64
   D.) 71

Answer: Option 'A'

72

  • 24. Out of 12 employs of a bank, one employ retires and his place, a new employ of age 24 years joins as a result average age of employs reduces by 4 years. The age of the retired employ is: 
   A.) 72
   B.) 62
   C.) 64
   D.) 71

Answer: Option 'A'

72

  • 25. A man covered a certain distance at a speed of 8 Kmph and returned at a speed of 4 Kmph. Find the average speed of whole journey? 
   A.) 3 ¾ Kmph
   B.) 5 1/3 Kmph
   C.) 4 ¼ Kmph
   D.) 2 ¼ Kmph

Answer: Option 'B'

5 1/3 Kmph

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