Discussion
Home ‣ Aptitude ‣ Numbers See What Others Are Saying!
- Question
(22 + 42 + 62 + ... + 202) =?
Options- A. 770
- B. 1155
- C. 1540
- D. 385 x 385
- Correct Answer
- 1540
Explanation
(2 2 + 4 2 + 6 2 + ... + 20 2 ) = (1 x 2) 2 + (2 x 2) 2 + (2 x 3) 2 + ... + (2 x 10) 2= (22 x 12) + (22 x 22) + (22 x 32) + ... + (22 x 102)
= 22 x [12 + 22 + 32 + ... + 102]
[ Ref: (12 + 22 + 32 + ... + n2) = 1 n(n + 1)(2n + 1) ] 6 = ❨ 4 x 1 x 10 x 11 x 21 ❩ 6 = (4 x 5 x 77)
= 1540.
- 1. A, B and C are employed to do a piece of work for $575. A and C are supposed to finish 19 / 23 of the work together. Amount shall be paid to B is:
Options- A. $210
- B. $100
- C. $200
- D. $475 Discuss
- 2. Which one of the following can't be the square of natural number?
Options- A. 32761
- B. 81225
- C. 42437
- D. 20164
- E. None of these Discuss
- 3. A number gets reduced to its one-third, when 48 is subtracted from it. What is two-third of that number?
Options- A. 24
- B. 72
- C. 36
- D. None of these Discuss
- 4. 100 oranges are bought at the rate of Rs. 350 and sold at the rate of Rs. 48 per dozen. The percentage of profit or loss is:
Options- A. 14 2⁄7% gain
- B. 15% gain
- C. 14 2⁄7% loss
- D. 15 % loss Discuss
- 5. E being always in the middle.
Options- A. 18 ways
- B. 24 ways
- C. 48 ways
- D. 20 ways Discuss
- 6. A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?
Options- A. 65 sec
- B. 89 sec
- C. 100 sec
- D. 150 sec Discuss
- 7. X can completed a job in 12 days. If X and Y work together, they can complete the job in 6 2/ 3 days, Y alone can complete the job in
Options- A. 10 days
- B. 12 days
- C. 15 days
- D. 18 days Discuss
- 8. Reena took a loan of Rs. 1200 with simple interest for as many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, what was the rate of interest?
Options- A. 3.6
- B. 6
- C. 18
- D. Cannot be determined
- E. None of these Discuss
- 9. Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train?
Options- A. 23 m
- B. 23 2⁄9 m
- C. 27 7⁄9 m
- D. 29 m Discuss
- 10. Find the number of ways, in which 12 different beads can be arranged to form a necklace .
Options- A. 11 !/2
- B. 10 !/2
- C. 12 !/2
- D. Couldn't be determined Discuss
More questions
Correct Answer: $100
Explanation:
Correct Answer: 42437
Explanation:
The square of a natural number never ends in 7.
∴42437 is not the square of a natural number.
Correct Answer: None of these
Explanation:
Let the number be N.
Then, N - N/3 = 48
2N/3 = 48.
Correct Answer: 14 2⁄7% gain
Explanation:
| C.P. of 1 orange = Rs. | ❨ | 350 | ❩ | = Rs. 3.50 |
| 100 |
| S.P. of 1 orange = Rs. | ❨ | 48 | ❩ | = Rs. 4 |
| 12 |
| ∴ Gain% = | ❨ | 0.50 | x 100 | ❩% | = | 100 | % = 14 | 2 | % |
| 3.50 | 7 | 7 |
Correct Answer: 24 ways
Explanation:
When E is fixed in the middle, then there are four places left to be filled by four remaining letters O, M, G and A and this can be done in 4! ways.
? Total number of ways = 4! = 24
Correct Answer: 89 sec
Explanation:
| Speed = | ❨ | 240 | ❩m/sec = 10 m/sec. |
| 24 |
| ∴ Required time = | ❨ | 240 + 650 | ❩sec = 89 sec. |
| 10 |
Correct Answer: 15 days
Explanation:
X's 1 day's work = 1/12
(X + Y)' s 1 day's work = 3/20
? Y's 1 day's work = (3/20) - (1/12) = 4/60 = 1/15
? Number of day's taken by Y to complete the work = 15 days
Correct Answer: 6
Explanation:
Let rate = R% and time = R years.
| Then, | ❨ | 1200 x R x R | ❩ | = 432 |
| 100 |
⟹ 12R2 = 432
⟹ R2 = 36
⟹ R = 6.
Correct Answer: 27 7⁄9 m
Explanation:
| Relative speed = (40 - 20) km/hr = | ❨ | 20 x | 5 | ❩ | m/sec = | ❨ | 50 | ❩ | m/sec. |
| 18 | 9 |
| ∴ Length of faster train = | ❨ | 50 | x 5 | ❩ | m = | 250 | m = 27 | 7 | m. |
| 9 | 9 | 9 |
Correct Answer: 11 !/2
Explanation:
Number of arrangements of beads = (12 - 1) !, but it is not mentioned that either it is clockwise or anti - clockwise .
So, required number of arrangements = [(12 - 1)! ] / 2 = 11 !/2
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.