Logarithms
Test
Model Test
Ebook
Quiz-1 : Numbers, General Mathematics
Quiz-2 : HCF & LCM, General Mathematics
Quiz-3 : Decimal Fractions, General Mathematics
Quiz-7 : Percentage, General Mathematics
Quiz-8 : Profit and Loss, General Mathematics
Quiz-10 : Partnership, General Mathematics
Quiz-11 : Time & Work, General Mathematics
Index
General Mathematics Home
HCF & LCM
49
Numbers
118
Decimal Fractions
80
Roots
1
Percentage
114
Profit and Loss
32
Compound Interest
44
Average
54
Surds and Indices
35
Ratio & Proportion
107
Time & Work
47
Partnership
20
Simplification
94
Simple Interest
61
Area & Volume
113
Logarithms
41
Discount
17
Problems On Boats & Streams
14
Area
98
Chain Rule
17
odd man out and series
47
Alligation or Mixture
23
Latest Questions
139
Rances & Games of Skill
59
Schools
Ebook
Question:
If` log_32 x = 0.8,` then x is equal to :
A
`25.6`
B
`16`
C
`10`
D
`12.8`
Note:
`log_32 x = 0.8 ⇔ x = (32)^0.8` `= (2^5)^4/5` `= 2^4` `= 16.`
Show answer
Show Note
Report
Question:
If`log_4 x + log_2 x = 6,` then x is equal to :
A
`2`
B
`4`
C
`8`
D
`16`
Note:
`log_4 x + log_2 x` `= 6 ⇔ (log x)/(log 4) + (log x)/(log 2)` `= 6` `:. (log x)/(2 log 2) + (log x)/(log 2)` `= 6 ⇔ 3 log x` `= 12 log 2` `or log x` `= 4 log 2 ⇔ log x` `= log ^24 or x = 2^4` `= 16.`
Show answer
Show Note
Report
Question:
If`log_8 x + log_8 1/6 = 1/3,` then the value of x is :
A
`12`
B
`16`
C
`18`
D
`24`
Note:
`log x + log_8 1/6` `= 1/3 ⇔ (1og x)/(log 8) + (log 1/6)/(log 8)` `= 1/3` `:. log x + log 1/6` `= 1/3 log 8` `or log x + log 1/6` `= log (8^1/3)` `= log (2^3)^1/3.` `:. log x + log 1/6` `= log 2` `or log x` `= log 2 - log 1/6` `= log (2 xx 6/1)` `= log 12.` `:. x = 12.`
Show answer
Show Note
Report
Question:
If`log 2 = 0.30103,` then the number of digits in`4^50` is :
A
`30`
B
`31`
C
100`
D
`200`
Note:
`log ^4^50` `= 50 log 4` `= 50 log 2^2` `= (50 xx 2) log 2` `= 100 xx log 2` `= (100 xx 0.30103)` `= 30.103.` :. Characteristic`= 30.` Hence the number of digits in`4^50` is `31`
Show answer
Show Note
Report
Question:
If`log 2 = 0.30103,` then the number of digits in `4^50` is :
A
`14`
B
`16`
C
`18`
D
`25`
Note:
`log_5^20` `= 20 log 5` `= 20 xx [log (10/2)]` `= 20 xx [log 10 - log 2]` `= 20 xx [1 - 0.3010]` `= 20 xx .6990` `= 13.9800` :. Characteristic`= 13`. :. Number of digits in`5^20` is `14`.
Show answer
Show Note
Report
Question:
The value of log`(-1/3)^81` is equal to :
A
`- 27`
B
`- 4`
C
`4`
D
`27`
Note:
Let log`(- 1/3)^81` `= x.` Then,` (- 1/3)^x` `= 81 = 3^4` `= (- 3)^4` `= (- 1/3).` `:. x = - 4.`
Show answer
Show Note
Report
Question:
The value of `log_2√3 (1728)`is equal to :
A
`3`
B
`5`
C
`6`
D
`9`
Note:
Let` log2√3 (1728) = x.` Then, `(2√3)^x = 1728` `= (12)^3 = [(2√3)^2]^3` `= (2√3)^6.` `:. x = 6`
Show answer
Show Note
Report
Question:
The value of `log_2 (log_5 625)` is :
A
`2`
B
`5`
C
`10`
D
`15`
Note:
Let `log_5 625 = x.` Then,`5^x = 625` `= 5^4 or x = 4.` Let `log_2 (log_5 625) = y.` Then,`log_2 (4) = y` `or 2^y = 4 = 2^2.` So,`y = 2.` :.`log_2 (log_5 625) = 2.`
Show answer
Show Note
Report
Question:
The value of`(1/3 log_10 125 - 2log_10 4 + log_10 32)` is :
A
`0`
B
`4/5`
C
`2`
D
`1`
Note:
`1/3 log_10 125 - 2log_10^4 + log_10^32` `= log_10 (125)^1/3 - log_10 (4^2) + log_10 ^32` `= log_10 16 + log_10^32` `= log_10 ((5 xx 32)/(16))` `= log_10^10` `= 1.`
Show answer
Show Note
Report
Question:
`[log (a^2/(bc)) + log (b^2/(ac)) + log (c^2/(ab))]` is equal to :
A
`0`
B
`1`
C
`2`
D
`abc`
Note:
Not available
Show answer
Show Note
Report
First
Prev
1
2
3
4
Next
Last
/5
Go
Schools
App Store
Whiteboard
Blogs
Quiz
Test
Apply Course
Games
Freelancers
Professionals
Newspapers
Terms
Privacy
Copyright © 2024. Powered by
Intellect Software Ltd