Average problems
- 1. The average age of A, B , C, D five years ago was 45 years . by including P, the present average age of all the five is 49 years . the present age of P is?
Options- A. 64 years
- B. 48 years
- C. 45 years
- D. 40 years Discuss
Correct Answer: 45 years
Explanation:
Present age of P = [(49 x 5 ) - (4 x 45 + 4 x 5 ) ] years
= 45 years.
- 2. Out of three number, the first is twice the second and is half of the third. If the average of the three number is 56, the three number on order are?
Options- A. 48, 96, 24
- B. 48, 24, 96
- C. 96, 24,48
- D. 96, 48, 24 Discuss
Correct Answer: 48, 24, 96
Explanation:
Let the numbers be 2y, y and 4y
? Average = (2y + y + 4y)/3
? 7y/3 = 56
? y = (3 x 56) / 7 = 24
Hence , the number in order are 48, 24 and 96
- 3. The sum of seven numbers is 235. The average of the first three is 23 and that of the last three is 42. The fourth number is?
Options- A. 40
- B. 126
- C. 69
- D. 195 Discuss
Correct Answer: 40
Explanation:
Sum of 7 numbers = sum of first 3 numbers + N4 + sum of last 3 numbers.
(23 x 3) + N4 + (42 x 3) = 235
? N4 = 40
? 4th number = 40
- 4. Find the average of the following set of scores 253, 124, 255, 534, 836, 375, 101, 443, 760
Options- A. 427
- B. 413
- C. 141
- D. 490 Discuss
Correct Answer:
Explanation:
Required average = (Sum of all scores) / (Number of scores)
= (235 + 124 + 255 + 534 + 836 + 375 + 101 + 433 + 760)/9
= 3681/9= 409
- 5. Find the average of the following set of scores. 124, 856, 331, 227, 963, 338, 259, and 662
Options- A. 570
- B. 660
- C. 141
- D. 350 Discuss
Correct Answer:
Explanation:
Required average = ( Sum of scores) / (No of scores)
= (124 + 856 + 331 + 227 + 963 + 338 + 259 + 662)/8
= 3760/8 = 470
- 6. Find the average of all prime numbers between 60 and 90.
Options- A. 72
- B. 74.7
- C. 74
- D. 73.6 Discuss
Correct Answer: 74.7
Explanation:
Average of all prime numbers between 60 and 90
= (61 + 67 + 71 + 73 + 79 + 83 + 89)/7
= 523/7 = 74.7
- 7. The average of nine numbers is 50. The average of the first five numbers is 54 and that of the last three numbers is 52. Then the sixth number is
Options- A. 34
- B. 24
- C. 44
- D. 30 Discuss
Correct Answer: 24
Explanation:
Required number = (Sum of all numbers) - [(Sum of first 5 numbers) + (Sum of last 3 numbers)
= 50 x 9 - ( 54 x 5 + 3 x 52)
= 450 - (270 + 156) = 450 - 426 ? 24
- 8. The Average of six observation is 12. The average decreases by 1 when a new observation is included. What is the seventh observation?
Options- A. 1
- B. 3
- C. 5
- D. 6 Discuss
Correct Answer: 5
Explanation:
Total of 6 observation = 6 x 12 = 72
Total of 7 observation (including the 7th) = 7 x (12 - 1) = 77
? 7th observation = 77 - 72 = 5
- 9. Average to ten number is 7 . If every number is multiplied by 12, What will be the average of new numbers?
Options- A. 7
- B. 9
- C. 82
- D. 84 Discuss
Correct Answer: 84
Explanation:
Here initial average = 7
As we know that, if all the numbers are multiple by a certain number, then their average must be a multiple of that number.
? New average = 7 x 12 = 84
- 10. The average weight of 60 students in a class was calculated to be 40 kg. Later it was found out that the weight of one of the students was calculated as 36 kg, whereas his actual weight was 33 kg. What is the actual average weight of the students in the class?
Options- A. 39.90 kg
- B. 39.95 kg
- C. 39 kg
- D. 38 kg Discuss
Correct Answer: 39.95 kg
Explanation:
Total correct weight = (40 x 60) - 36 + 33 = 2400 - 3 = 2397 kg
? Required average weight = 2397/60 = 39.95 kg
More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.