Logarithm problems
- 1. If logx y = 100 and log2 x = 10, then the value of y is:
Options- A. 210
- B. 2100
- C. 21000
- D. 210000 Discuss
Correct Answer: 21000
Explanation:
∴ logx y = 100
⟹ y = x100
⟹ y = (210)100 [put value of x]
⟹ y = 21000.
- 2.
log √8 is equal to: log 8
Options- A.
1 √8 - B.
1 4 - C.
1 2 - D.
1 8
Discuss
Correct Answer:
| 1 |
| 2 |
Explanation:
| log √8 | = | log (8)1/2 | = | ½log 8 | = | 1 | . |
| log 8 | log 8 | log 8 | 2 |
- 3.
If logx ❨ 9 ❩ = - 1 , then x is equal to: 16 2
Options- A.
- 3 4 - B.
3 4 - C.
81 256 - D.
256 81
Discuss
Correct Answer:
| 256 |
| 81 |
Explanation:
| logx | ❨ | 9 | ❩ | = - | 1 |
| 16 | 2 |
| ⟹ x-1/2 | = | 9 |
| 16 |
| ⟹ | 1 | = | 9 |
| √x | 16 |
| ⟹ √x = | 16 |
| 9 |
| ⟹ x = | ❨ | 16 | ❩ | 2 |
| 9 |
| ⟹ x = | 256 |
| 81 |
- 4. If log 27 = 1.431, then the value of log 9 is:
Options- A. 0.934
- B. 0.945
- C. 0.954
- D. 0.958 Discuss
Correct Answer: 0.954
Explanation:
⟹ log (33 ) = 1.431
⟹ 3 log 3 = 1.431
⟹ log 3 = 0.477
∴ log 9 = log(32 ) = 2 log 3 = (2 x 0.477) = 0.954.
- 5.
The value of ❨ 1 + 1 + 1 ❩ is: log3 60 log4 60 log5 60
Options- A. 0
- B. 1
- C. 5
- D. 60 Also asked in: Bank Exams, Bank PO
Correct Answer: 1
Explanation:
| Given expression | = log60 3 + log60 4 + log60 5 |
| = log60 (3 x 4 x 5) | |
| = log60 60 | |
| = 1. |
- 6. If log 2 = 0.3010, then the number of digits in 2 64 is?
Options- A. 18
- B. 19
- C. 20
- D. 21 Discuss
Correct Answer: 20
Explanation:
Required answer = [64 log10 2] + 1
= [ 64 x 0.3010 ] + 1
= 19.264 + 1
= 19 + 1
= 20
- 7. The value of $ \frac{\log_{a}{x}}{\log_{ab}{x}} - \log_{a}{b}$ is?
Options- A. 0
- B. 1
- C. a
- D. ab Discuss
Correct Answer: 1
Explanation:
? loga x = ( logabx) / (logaba)
? The given expression = [[(logabx) / (logaba)] / [( logabx )] - ( logab)
= (1/logaba) - logab = logaab - logab = loga(ab/b)
= logaa = 1
- 8. The value of log 23 x log 32 x log 34 x log 43 is?
Options- A. 1
- B. 2
- C. 3
- D. 4 Discuss
Correct Answer: 1
Explanation:
Given Exp.= log23 x log 32 x log34 x log43
= (log3 / log2) x ( log2 / log3) x (log4 / log3) x (log3 / log4) = 1
- 9. Given that log 10 2 = 0.3010, then log 2 10 is equal to?
Options- A. 0.3010
- B. 0.6990
- C. 1000 / 301
- D. 699 / 301 Discuss
Correct Answer: 1000 / 301
Explanation:
log2 10 = log 10 / log 2
= 1 / log 2
= 1.0000 / 0.3010
= 1000 / 301
- 10. The value of log 9/8 - log 27/32 + log3/4 is?
Options- A. 0
- B. 1
- C. 2
- D. 3 Discuss
Correct Answer: 0
Explanation:
Given Exp. = log [{(9/8) / (27/32)} x 3/4)]
= log [(9/8) x (3/4) x (32/27)]
= log 1
= 0
More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.