Average problems
- 1. A family consists of two grandparents, two parents and three grandchildren. The average age of the grandparents is 67 years, that of the parents is 35 years and that of the grandchildren is 6 years. What is the average age of the family?
Options- A. 284⁄7 years
- B. 315⁄7 years
- C. 321⁄7 years
- D. None of these Discuss
Correct Answer: 315⁄7 years
Explanation:
| Required average |
|
|||||
|
||||||
|
||||||
|
- 2. The captain of a cricket team of 11 members is 26 years old and the wicket keeper is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team. What is the average age of the team?
Options- A. 23 years
- B. 24 years
- C. 25 years
- D. None of these Discuss
Correct Answer: 23 years
Explanation:
Let the average age of the whole team by x years.
∴ 11x - (26 + 29) = 9(x -1)
⟹ 11x - 9x = 46
⟹ 2x = 46
⟹ x = 23.
So, average age of the team is 23 years.
- 3. In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?
Options- A. 67 kg.
- B. 68 kg.
- C. 69 kg.
- D. Data inadequate
- E. None of these Discuss
Correct Answer: 67 kg.
Explanation:
Let Arun's weight by X kg.
According to Arun, 65 < X < 72
According to Arun's brother, 60 < X < 70.
According to Arun's mother, X <= 68
The values satisfying all the above conditions are 66, 67 and 68.
| ∴ Required average = | ❨ | 66 + 67 + 68 | ❩ | = | ❨ | 201 | ❩ | = 67 kg. |
| 3 | 3 |
- 4. If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:
Options- A. 53.33
- B. 54.68
- C. 55
- D. None of these Discuss
Correct Answer: 54.68
Explanation:
| Required average |
|
|||||
|
||||||
|
||||||
| = 54.68 |
- 5. The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is:
Options- A. 17 kg
- B. 20 kg
- C. 26 kg
- D. 31 kg Discuss
Correct Answer: 31 kg
Explanation:
Let A, B, C represent their respective weights. Then, we have:
A + B + C = (45 x 3) = 135 .... (i)
A + B = (40 x 2) = 80 .... (ii)
B + C = (43 x 2) = 86 ....(iii)
Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)
Subtracting (i) from (iv), we get : B = 31.
∴ B's weight = 31 kg.
- 6. The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is:
Options- A. 3500
- B. 4000
- C. 4050
- D. 5000 Discuss
Correct Answer: 4000
Explanation:
Let P, Q and R represent their respective monthly incomes. Then, we have:
P + Q = (5050 x 2) = 10100 .... (i)
Q + R = (6250 x 2) = 12500 .... (ii)
P + R = (5200 x 2) = 10400 .... (iii)
Adding (i), (ii) and (iii), we get: 2(P + Q + R) = 33000 or P + Q + R = 16500 .... (iv)
Subtracting (ii) from (iv), we get P = 4000.
∴ P's monthly income = Rs. 4000.
- 7. The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options- A. 0
- B. 1
- C. 10
- D. 19 Discuss
Correct Answer: 19
Explanation:
Average of 20 numbers = 0.
∴ Sum of 20 numbers (0 x 20) = 0.
It is quite possible that 19 of these numbers may be positive and if their sum is a then 20th number is (-a).
- 8. In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in the remaining 40 overs to reach the target of 282 runs?
Options- A. 6.25
- B. 6.5
- C. 6.75
- D. 7 Discuss
Correct Answer: 6.25
Explanation:
| Required run rate = | ❨ | 282 - (3.2 x 10) | ❩ | = | 250 | = 6.25 |
| 40 | 40 |
- 9. A grocer has a sale of Rs. 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs. 6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs. 6500?
Options- A. Rs. 4991
- B. Rs. 5991
- C. Rs. 6001
- D. Rs. 6991 Discuss
Correct Answer: Rs. 4991
Explanation:
Total sale for 5 months = Rs. (6435 + 6927 + 6855 + 7230 + 6562) = Rs. 34009.
∴ Required sale = Rs. [ (6500 x 6) - 34009 ]
= Rs. (39000 - 34009)
= Rs. 4991.
- 10. A car owner buys petrol at Rs.7.50, Rs. 8 and Rs. 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if he spends Rs. 4000 each year?
Options- A. Rs. 7.98
- B. Rs. 8
- C. Rs. 8.50
- D. Rs. 9 Discuss
Correct Answer: Rs. 7.98
Explanation:
| Total quantity of petrol consumed in 3 years |
|
||||||||||||
|
|||||||||||||
|
Total amount spent = Rs. (3 x 4000) = Rs. 12000.
| ∴ Average cost = Rs. | ❨ | 12000 x 51 | ❩ | = Rs. | 6120 | = Rs. 7.98 |
| 76700 | 767 |
More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.